Infrared thermometers, also called non-contact handheld thermometers, have been gaining a strong foothold globally since the early 2000s. These affordable lightweight thermometers have different applications. However, their use primarily focuses on checking humans temperature. Doctors praise the medical-grade infrared thermometers well for their quick temperature results and accuracy.

You can use an infrared thermometer to measure the body’s temperature without actually bringing the device close to contact, which is advantageous in case of viral infections like the Coronavirus affecting the entire world since January 2020. Plus, they are non-invasive, making it less complicated for anybody to use.

Although they are being used in hospitals in the US and globally, and by tons of people at home, some folks still think infrared thermometers are harmful to babies and some parts of the human body such as the eye. Could this be unfounded, or is it just that the idea that the thermometer uses infrared is scary to some folks? Well, not to worry, this piece is primarily aimed at breaking open the questions surrounding the safety of infrared thermometers on humans. Without further ado, let’s dive in.


There are three grades of infrared thermometers according to various uses and accuracy. They are industrial-grade, medical-grade infrared and, consumer-grade infrared thermometers. However, the industrial-grade thermometers are not accurate enough; hence they aren’t used much by people. The medical-grade infrared thermometers are the ones used in hospitals and by most people in the world. Medical-grade infrared thermometers are those with the highest accuracy requirements, which is between 0.1 and 0.2 degrees.


At this point, you must be asking if you can use an infrared thermometer on humans. Well, that’s easy to answer. Infrared thermometers are safe to use on humans and do not lead to any harm. So far, there’s been no case of injury reported of medical-grade IR thermometers.

Another thing is infra-red thermometers do not cause eye damage. According to Feng Luzhao, a researcher from the Chinese Center for Disease Control and Prevention, using infrared thermometers is not harmful to the eyes and body.

Do infrared thermometers emit radiation? This is a common question posed by people who hesitate to use IR thermometers. Based on how infrared thermometers work, they do not emit radiation. IR thermometers only measure radiation emitted from human skin. However, it would be best if you use an IR thermometer that is FDA approved. This means it has been tested and stamped safe for use on adults and babies.

However, laser-guided models, although normally harmless, should not be targeted near the eyes as even low power lasers can damage the eyes. So, for medical applications, it is recommended that you use non-laser guided models for safety reasons. So there’s no need to worry about using an infrared thermometer on your baby or adult at all.


When your kids feel sick, the first thing you do is check for a fever, and infrared thermometers are a sure way of getting an accurate temperature result. Infrared thermometers are safer than mercury thermometer because mercury is dangerous to humans. IR thermometers don’t harm kids’ body parts as they don’t have radiation. These thermometers work by reflecting the infrared wavelength of heat dissipation from the human body. However, they use batteries to function, and if kids swallow them, they can become harmful.

Knowing how to use an infrared thermometer on a baby makes it easier to get accurate temperature results. The steps are simple to follow.

  1. Hold the infrared sensor above your subject, and press down the button.
  2. The e-digital display will bring up the temperature reading, accurate to 0.4°F (0.2°C), with a matching color code.
  3. Wait and repeat. Store up to 64 temperature readings so you can track the progress of your kid’s fever.

Also, for kids three months to 3 years, the American Academy of Pediatrics (AAP) recommends using rectal, axillary (underarm), or tympanic (in-ear) for the most accurate readings. The AAP recommends these infra-red thermometer type of tests as your kid grows: Under three months (Rectal), three months to 3 years(rectal, axillary, and tympanic). 4 to 5 years (rectal, oral, axillary, and tympanic), and five years to adult (Oral, axillary, and tympanic)


Infrared thermometers are entirely safe for use on humans, including kids, but you must know how to use it well, so you don’t get the wrong temperature check. Anyone who holds an infrared thermometer would find them light, super easy to use, and possessing a fast reaction time. It gives accurate temperature results due to its advanced technology, and quite durable so you wouldn’t need to worry about it being damaged from a fall anytime soon. Fears that IR thermometers are harmful to kids are unfounded generally. IR thermometers are the safest method of checking your kid’s temperature without any fuss.

Infrared light or infrared radiation is a light source that humans can’t see. However, you can sense the high temperatures of infrared light. When in daylight, you expose the human eye to short wavelengths of infrared radiation. In the home, there are many devices that utilize infrared light to operate electronics.

So how can this invisible light affect your eyesight? Can it damage your eyes or is it harmless? Continue reading to find out what infrared light is, what it’s commonly used for, and how it can affect your eyesight.

What is Infrared Light?

Infrared light is a type of electromagnetic radiation at wavelengths between 780nm and 1000µm. There are three different spectrums that divide light:

  • Near infrared (NIR) with wavelengths of 0.78~3.0µm
  • Mid infrared (MIR) with wavelengths of 3.0~50.0µm
  • Far infrared (FIR) with wavelengths of 50.0~1000µm

Atoms are absorbed and subsequently release energy causing the effects of infrared light. Electromagnetic radiation will include the following from highest to lowest frequencies:

  • Gamma rays
  • X-rays
  • UV radiation
  • Visible light
  • Infrared radiation
  • Radio waves
  • Microwaves

All of these types of radiation frequencies make up the electromagnetic band.

The wavelengths of infrared light are longer than visible light and that’s why humans can’t see it. As mentioned before we can feel the heat of infrared light. Additionally, all objects emit some form of infrared radiation. The human body emits infrared as well as animals, electronics, fire and the sun.

The Use of Infrared Light

Since the discovery of infrared light in 1800 by William Herschel, innovators have designed an array of devices for residential, commercial and industrial applications, using this type of light. In this section, we’ll discuss what infrared is commonly used for.

In the Home

There are many items in the home that use infrared to operate. Luckily, these items emit low range infrared so they won’t have a negative effect on your eyesight.

TV Remotes

An infrared light inside a remote carries a signal from the remote to a device it controls to operate it. Remotes change channels on TVs, operate light switches, turn on AC systems and prompt gate motors.

Incandescent Light Bulbs

Incandescent light bulbs emit 95% of their electrical energy as infrared light.

Infrared Lamps

An infrared lamp heats up bathrooms, saunas and there are types that warm plates & cups. Furthermore, these lamps heat up tanks for reptile pets such as bearded dragons and snakes.

On the Job

Since infrared wavelengths are invisible to the human eye, there are devices such as infrared cameras that assist plumbers and electricians to locate pipes & wires. Hunters use infrared optics to see animals behind thick bushes and firefighters use the devices to locate people in buildings.

The Effects of Infrared Lights on the Eyes

Infrared light in high concentrations and intensity can have a negative effect on the eyes. The development of new technologies brought about stronger sources of infrared light. High exposure to infrared light can cause eye damage, such as retinal burns from welding.

The exposure to infrared light has been connected to many eye injuries caused mainly by the thermal effects of the light. The wavelengths associated with these injuries range between 780nm and 1400nm.

Note that incandescent bulbs and infrared lamps aren’t powerful enough to cause extreme damage to the eyes. However, you should never stare directly into any light source, such as the sun or bulbs, for long periods of time because it can cause irreversible damage to the retina.

When you stare at a light source, the ultraviolet rays can harm the tissue of parts of the eye, like the retina. This is what happens when you stare directly at the sun and the short term damage is called solar keratitis. Symptoms of solar keratitis include pain, inflammation and light sensitivity.

High-intensity damage caused by infrared light is called solar retinotopy which is the result of UV light burning holes in the retina part of the eye. It causes central blind spots known as scotoma.

Infrared Light Therapy

Intense infrared light can damage the eyes but studies show that the use of it can reverse the effects of light damage to the retina. A treatment called red light therapy heals skin and muscle tissue. The red light distributes low levels of near-infrared light.

This type of therapy is also known as low level laser therapy (LLLT), photobiomodulation, and low power laser therapy. Studies show that it’s safe for the eyes and has the potential to protect your vision. Red light therapy increases the healing process of people who have inflammation or damaged eyes.

Red Light Therapy Explained

Natural light stimulates mitochondria in your cells which increases the production of Adenosine 5-triphosphate (ATP). The ATP is the molecule responsible for storing and transferring energy in cells. The red light therapy fights against macular degeneration which optimizes the cells inside your eyes, even as you age. Therefore, high quality red light therapy devices can deliver safe wavelengths of natural light to increase cellular energy production.

These devices have integrated medical LEDs that shine natural red and near infrared light onto your body. This acts similar to the wavelengths produced by the sun but without the UV rays and heat. This is an example of how the benefits of infrared light can be harnessed to serve a great purpose.

To clarify, in order to perform red light therapy, people stand in front of a red lamp between six and 15 minutes a day. This will give the mitochondria in the cells the natural light they need to accelerate the energy that powers your body.

Final Thoughts

To sum up, high intensity infrared exposure can damage the eyes and cause loss of vision. But low near-infrared light can assist with healing the body and the eyes. There have been studies in the past that state that near infrared light can stop further damage to retinal cells and prevent blindness. It’s all about how you use this valuable resource.

Infrared thermometers have been growing in popularity. They’re very fast and accurate to use, and, especially for those with small children, the fact that you don’t need to stick them under a tongue or into an ear can make them much easier to use than other digital thermometers.

It’s common, however, to worry that using an infrared thermometer may be somewhat dangerous. Usually, people are worried about one of two things: A) they’re worried about potential side effects from the use of the thermometer or B) they’re worried that the thermometer won’t give them an accurate temperature reading, which could potentially place them or their child into a medically dangerous situation.

We will briefly examine these possibilities and help you to understand whether or not an infrared thermometer is safe to use.

Potential Side Effects of Infrared Thermometer

First, let’s look at the potential side effects of using an infrared thermometer. Infrared thermometers usually project a small laser, and it’s fair to wonder if that laser might be harmful. The answer is that these lasers are completely harmless.

If the laser were powerful enough to present a danger to you, it would be strong enough to damage your eyes the instant you switched the thermometer on. This laser is no more powerful than those that are used in laser pointers, and may, in fact, be even weaker than they are. While it’s true that laser pointers can be hazardous when shined directly into the eye, that’s not how you’ll be using the thermometer.

It’s also common to worry that the thermometer might cause damage via infrared radiation. To help you understand why you don’t need to worry about that, let’s briefly go over how infrared thermometers work.


While it’s understandable that many people have concerns about using infrared thermometers, there really is no danger. Most of these concerns stem from misunderstandings about the thermometers themselves.

Since the thermometer does not generate infrared radiation, there’s no risk of if causing any harm to the user through radiation damage. Likewise, on models which have a laser, the laser exists solely for the purpose of helping to aim the thermometer, nothing more, and it’s so low powered that there’s no risk of harm.

Finally, the only times when infrared thermometers have been found to give inaccurate temperature readings have been situations in which the user did not follow the instructions properly, and therefore the inaccurate readings were the result of user error.

As long as you follow the instructions and use it properly, an infrared thermometer is perfectly safe to use and has a number of advantages over other thermometer types.

Infrared thermometers are very useful products that have become quite “popular” during the global COVID-19 crisis. While this is not really the best way to become popular, temperature guns are here to stay. They can assess your temperature quite accurately, without any kind of physical contact, which is very helpful in situations when contagion is possible. Using an infrared thermometer for fever is just the most typical scenario. There are many other situations when this product can come in handy and we’ll mention some of them in this text.

Pet owners usually have problems with measuring the temperature of their beloved animal friends. This is not only frustrating but also dangerous, as pets (that is, mammals) can also suffer from fever just as we humans do. You can also use it in the kitchen or the backyard when cooking with the high temperatures. It is a great way to check the temperature of your frying pan or grill when you need some specific temperature for your meal. This way you don’t have to use the classic kitchen thermometer which has needles that are used to see the temperature, which will result in a juicier end product since you’re not poking it and losing all of the juicy goodness out of your roast.

How Do Infrared Thermometers Work?

They work from a distance and without any contact with the person or a surface. The infrared thermometer gun accuracy is excellent, it is usually ± 2 °C or  ±4 °F which is very precise and there is no great difference between reality and results, which unfortunately isn’t the case with things like elections.

We get the temperature immediately, with no contact, using only infrared laser technology. The information “comes” from the thermal radiation and infrared energy that a person or an object gives off. They are shaped like guns because this allows easier use and more precise results. You can also retake a temperature if you are not sure- this is also a good way to assess the reliability of your product. If you know that an object emits a constant amount of heat, repeated measures should give the same result. If this is not the case, you might want to contact the manufacturer.

Frankly, the principles behind measuring temperature are quite complex, so we won’t go into many details here- not simply because we’d like to spare you the hassle, but also because we tended not to pay attention during physics classes. Anyways, a typical temperature gun works by picking up (registering) the infrared signals which are emitted by a body. Phew, that was actually simpler than we expected!

It’s important to note that the person who’s using the gun also emits infrared signals (heat) which can ruin the measuring process. This is why you need to follow the instructions closely, in order to get the most reliable results possible.

Infrared Thermometers Basics

It is highly accurate, and there is almost no waiting time, so the results are coming very quickly. Since there is no contact with a person or an object, it can be used again right after the previous use, there is no need to do some deep and complicated cleaning of the gun. Every model has its instruction manual, so be sure to consult with it.

Medical infrared thermometers are in need now, especially with the current pandemic situation in the whole world and the war we are constantly battling against COVID 19. It is important to take care of our health, and your body temperature using the infrared thermometer has never been more fast and safe to use.

When fighting COVID 19 infrared thermometer is extremely useful, as it can read the body temperature of the person quickly and precisely, with no contact, which leads to fast and safe check-ups. With the current worldwide situation, most states are monitoring their borders and passengers’ health in the possible prevention of a new outbreak and NCITs are indispensable for winning this great battle.

If you are looking for an FDA approved infrared thermometer you’ll be able to find some on Amazon and other websites- you’d just need to read the product description attentively.

Only the best laser thermometers have FDA certificates, along with many other certificates that are proving their good quality and special status among other brands.

Step By Step Guide to using an infrared thermometer?

The first benefit of using non- contact infrared thermometer (NCIT) is a distance between it and a person or object in question. You don’t want no corona lurking behind your back, so be happy whenever you see infrared guns being used. An infrared thermometer is best used out of direct sunlight and away from any other heat source. Other heat sources, even natural body temperature, can distort the results. This is why lately you can see a lot of people being tested at the airport, more specifically, at the terminals. Here, there is no direct sunlight, the room temperature is ideal, which will result in the most precise measuring.

Not all NCITs are used in the same way. There are some more or less important differences between them. It is very important to follow the instructions strictly because it will give you the best performance and it will prolong the life of your NCIT. Here are some basic rules that should be followed:

  • the place where the NCIT is used should be out of the sun and out of direct heat 
  • the environmental temperature should be around 60.8-104 ºF (16-40 ºC)
  • NCIT should be in testing place 10-30 minutes before using, so it can accommodate to environmental conditions

The person who is being evaluated should follow the next recommendations:

  • the forehead of the evaluated person should be clean, dry and there shouldn’t be any object blocking the NCIT (headbands, bandanas, caps) or any cosmetic product that could jeopardize the performance of NCIT gun.
  • the sensing area of NCIT should be dry and clean all the time, also a very important thing is not to touch the sensing area, as this will influence the final result
  • distance between the person and NCIT is different for each NCIT, therefore you should follow the instructions closely.

It’s impossible to emphasize enough that each infrared thermometer instruction manual can be different. Infrared thermometer distance from the forehead is very important and is usually specific for each NCIT guns, so don’t be surprised if you get peculiar results- you might simply be doing the wrong things. As is often the case, technology tends to work impeccably while humans are the ones who ruin everything with their impatience.

But there is no need to worry, NCTIs are mostly quite easy to use, and there is no need for some heavy preparations. It’s not like you need to be a rocket scientist to use it!

There is a lot of infrared thermometer brands, some are made for medical use only, and some are for broader use. The infrared thermometer price can also vary depending on their possibilities. The medical ones can be a bit pricier since they are made for the doctors, and usually have better quality. It depends on you, and your needs for which one you will decide to buy.

They use batteries, so you will find everything about them, their size, and any special type in their instruction manual. The infrared thermometer battery type is listed in the product description. Some of them use AA batteries, other ones use a regular 9-volt battery, and there is also an option for rechargeable batteries, for those who prefer this type.

Even when used continuously, they can last up to several hours, which is handy for medical staff or the border officers when they need to quickly check the temperature of passengers. Most NCTIs are made for single-handed use which allows you to be fast and efficient at every moment. Being said that they are made for single-handed use, it’s good to know that they are light and don’t take much space in the bag or on the desk.

Of course, like most other measuring products, these too have to be calibrated correctly. So how do you achieve infrared thermometer calibration? Most products have “MODE“ buttons on the side, along with some “DOWN“ and “UP“ buttons. First of all, insert the batteries and hold the “MODE“ button. Wait until F1 is displayed on the little screen. Then, proceed to measure something with an FDA approved body thermometer (which is working perfectly), and then do the same with the NCIT you want to calibrate. And when we say “measure something”, we mean anything- your dog, your stereo system, your husband, anything! Measuring the temperature might as well become your favorite hobby! But perhaps this is not the best idea, as you may get a bit paranoid if you realize that some metro passengers have a high temperature!

Back to business- after you compare the results given by two infrared thermometers, you will know how much difference is between the two. If the difference is less than 0.6C, then hold the “MODE“ button once more, until F1 is displayed again, and then with repeated pushes of the button, F3 will be displayed on the screen, and then using the “UP“ and “DOWN“ buttons you can insert the temperature difference. Finally, test it one last time to see if you’ve successfully calibrated your product.

Speaking of calibration, we should include instructions about how to make your infrared thermometer change to Fahrenheit. By default, most NCITs measure in degrees Celsius. This is simply because most countries use Celsius degrees. Like we’ve said before, press the “MODE“ button on the side of the thermometer, until F1 is displayed. At this stage, you can easily change the measuring option with “UP“ and “DOWN“ buttons. It is that simple, and it takes only a few quick steps to do it.

This specific instruction is sure to work with most infrared thermometer guns, but just to make sure, you should always read the manual that you get with the thermometer itself. Maybe some of them need some special steps and you wouldn’t’ want to miss out on them.

Where and How to Get One?

They can be bought almost anywhere, and along with the current pandemic situation that has struck the globe since the start of 2020, they have become more available and easier to find. But who has the time to bother and go outside, when you know that the disease is spreading as we speak?

You can buy them from the luxury of your own home! With a press of a button, to be exact. Infrared thermometers on Amazon can be a good pick since you can always see what others are saying about the product. It’s important to read the reviews regarding infrared thermometers, making sure that you won’t get a faulted one or such.

With the expansion of the global COVID 19 pandemic, there has been a large increase in demand for NCITs in the world- this situation is actually like a double-headed coin. While demand skyrocketed, the production also stepped up- NCIT price may have risen in the last period, as is the case with masks and other medical gear.

Infrared thermometer manufacturers in the USA mostly make reliable and durable products- the price might be less modest when compared with, say, Chinese temperature guns, so it’s your call. The USA is still the biggest exporter of the product, with more than 100 million dollars in annual sales. The biggest names out there are Exergen Corp from Watertown, Massachusetts, then we have Aoss Medical Supply from Monroe, Louisiana, and ThermoWorks. You can find them anywhere from 35$(the basic), all up to 100$, which are hospital grade infrared thermometers, way more advanced and mostly used by medical personnel, with an astonishingly accurate measuring technology, that can work for a long time and last for years.

No matter the cost, you should always look to get a high-quality infrared thermometer, durable, and long-lasting product. So look up on the Internet and see which brand is the most used one, and which one is the most used in your area since some manufacturers don’t place their products in certain countries.

Infrared Thermometer Pros and Cons:


Way faster than most methods out there delivers results in secondsIt is a bit more expensive than traditional thermometers


  Way safer than other methods out there, no need for direct physical contact


It requires a bit of tuning and figuring out how it works


  If calibrated correctly, gives precise results




Generally, the NCIT is the maybe the best option out there, not only because you don’t have to be in direct physical contact with the patient, but also because it is way faster than using some more traditional methods (mercury or digital methods).

Infrared Thermometer VS Oral Thermometer:

This one is rather obvious. Especially during the global pandemic situation, it is vital to make sure, especially for medical workers, to try and stay healthy and clean. With no direct contact with the patient, you can maintain the safe distance, while still getting body temperature results, and also it comes way faster than an oral thermometer.

Besides you’ll mostly find oral thermometers in cartoons- they are quite inconvenient, unreliable, and if you want to use the same apparatus with a lot of patients you need to disinfect it with each patient, and this can be a drag.

Infrared Thermometers VS Thermal Scanner:

The thing is that both of these work very similarly, yet there some differences. The NCIT measures average surface temperature of the spot it’s pointed to, and that spot can vary in size depending on the distance of the actual thermometer, while thermal scanners are not like this- they “shot” the “hotspots“ and “cold spots“ of a certain image. The principle, on the other hand, is the same.


Infrared Thermometers Vs Thermal Cameras:

The camera can get a much larger picture and analyze larger areas of one’s body. But unless you work as a border guard, you probably won’t use thermal cameras. They are expensive, and they aren’t the best when it comes to assessing body temperature accurately, which is the biggest upside of infrared thermometers. Sure, some high-tech thermal cameras give you the exact temperature of each part of your body, but these are used for scientific experiments.

Infrared Thermometers vs Digital Thermometers 

Digital is the new classic, most often being used by your mother when she suspects you have a fever. While the COVID-19 pandemic gave rise to the use of “thermal guns”, we can still see digital ones being used, especially for “home” purposes. Yes, you need to wait a bit with a digital method, and they are not that convenient since you’d usually put them below your armpit- but they still do the work.

Other Uses Of Infrared Thermometer 

This product will be quite useful even when the whole corona craze ends! How? Well, if you’re into cooking, you’re quite aware of the fact that getting the right temperature is crucial for making some tasty dishes. Sure, you don’t need high-tech equipment to boil an egg, but the situation changes a bit if you want to try some more complex recipes. In other words, using infrared thermometers as cooking accessories, besides making you feel like high-tech Gordon Ramsey, will help you make some nice meals.

Infrared thermometers and grilling is also a great combo- we’ve all ruined some nice meat while trying to show off our barbeque skills- this won’t happen again if you assess the temperature every now and then.

You can also use an infrared thermometer when your pet looks kind of sick, and see if there’s any reason to worry. You may not be aware of it, but there’s such thing as dog fever (if your dog’s temperature goes above 103 degrees F, you should consider getting it to a veterinarian). Cats can get fevers too- so having an infrared thermometer can help assess the temperature of your pets. Pets aren’t really that cooperative, even when it comes to routine medical checks. In other words, using a classic thermometer with your pet is next to impossible.

There isn’t really any boundary- you can use temperature guns to assess the state of your ventilation system for instance. Your computer sometimes shows you the temperature and warns you if overheating is possible, but this is not always the case- which is why you can use a temperature gun to assess the state of your processor and cooling system.


Is infrared thermometer dangerous?

Provided you follow the instructions and user manual, there won’t be any problems. Probably the biggest danger is that you can accidentally hit someone with it! Otherwise, it’s completely safe- there’s no physical contact, which means that there will be no virus transmission- which is always a possibility with classic thermometers. Some people wonder that infrared thermometer radiation is a problem. The truth is, many other technological gimmicks also use infrared signals, and nobody ever had any health problems.

How much does infrared thermometer cost?

As already mentioned, cost varies quite a bit. Medical-grade products are of course a bit more expensive- these products are used in critical situations, they need to be extremely accurate and durable. On the other hand, there’s a lot of new infrared thermometers that are “for personal use”, and these are usually a bit more accessible when it comes to cost. Even if you had an opportunity to purchase a medical-grade product, you should think twice because this product could have been used in hospitals- by purchasing thermometers that should be used by professionals you’re potentially depriving people who really need it. During the coronavirus era, when hospitals are overcrowded and there’s chronic need for high-quality medical products, you should pay attention to this.

Is infrared thermometer the best option for measuring temperature?

There’s a simple reason we’ve begun to see this product everywhere- it’s rather accurate, people can learn how to handle it quite quickly, there’s no physical contact (which means that one infrared thermometer can be used with an indefinite number of people), it’s efficient and time-saving. On the other hand, there are other methods for measuring temperature which might be more accurate and more valid, but they are of course more expensive and more time-consuming. Nowadays, when we need to test a lot of people quickly, infrared thermometers came in quite handy.

If you’re new to using forehead thermometers, you may be wondering if they’re really as accurate or more accurate than traditional thermometers. This is understandable, since with traditional thermometers you know that they’re taking the temperature reading inside the body rather than at the surface.

To help you understand how forehead thermometers can be accurate, we have to explain how they work.

How do Thermometers Work?

In order to understand how to properly use a thermometer, it’s helpful to know how thermometers work, first. All thermometers are tools for measuring heat. All of them, no matter the type, rely on a small amount of a substance that reacts to heat in specific ways to measure temperature.

Old-school mercury thermometers, for instance, rely on the expansion of mercury when exposed to heat. Because mercury responds to heat in a predictable way, it’s easy to use it as a way to measure temperature.

The reason why this works is that heat is actually a form of energy. At the atomic level, heat is movement. If you were to take a hot object and put it under a microscope next to a cold object, you’d see that the atoms in the hot object are moving around a lot more than the ones in the cold object.

Heat also works like air- it wants to move from areas of high pressure to low pressure. To understand this, you need to remember that “cold” is really just the absence of heat- you can’t actually measure how cold something is, you can only measure how much heat something has. When something is cold, it has very little heat.

If you put a cold object next to a hot one, the heat wants to even out by warming up the cold object. The rate at which this happens depends on what those objects are made of, because some materials conduct heat better than others. Metal is more conductive than wood, and silicon and rubber materials conduct heat so poorly that they can be used as insulators.

For a long time, most thermometers used metal to measure heat. Mercury is, in fact, a metal. It’s simply metal that is liquid at normal temperatures, which makes it very responsive to heat. Other thermometers, including the ones that come built in to a lot of grills, cheap oven thermometers, and the ones that come in your Thanksgiving turkey, are bimetal thermometers.

These thermometers use two different metal strips- often steel and copper- that are attached to each other and conduct heat at different rates. As they’re heated, the combined metal strips will bend in one direction, and they’ll bend in the other direction when they’re cooled. These are popular because they’re cheap, but they’re also very inaccurate.

Thermometers that rely on metals responding to heat to measure a temperature are imprecise and bimetal thermometers especially can be off by 5-10 degrees. They also take a relatively long time to give you a temperature reading. This why professionals in fields that require regular temperature readings- chefs and doctors- almost always prefer digital thermometers.

Most digital thermometers use a sensor called a thermoresistor. These are usually a small piece of glass with two wires attached. As the glass heats up, it’s resistance to the flow of electricity changes. A small computer in the thermometer can detect that change, and uses it to calculate a much more accurate temperature reading. What’s more, these are often instantaneous readings.

How Forehead Thermometers Work

Infrared thermometers have been used by doctors for a long time- if you can remember the doctor taking your temperature through your ear, that was an infrared thermometer like this one. Since children and infants often find the sensation of having the thermometer in their ear very unpleasant, these thermometers didn’t catch on at home.

The development of forehead thermometers changed that. These thermometers are also infrared thermometers, but they can measure body temperature on the forehead, or more accurately in the temporal artery. This is a completely comfortable process, which makes it very easy to take a child’s temperature. Because it’s such a kid-friendly technique, it’s becoming popular as an in-home thermometer.

How Infrared Thermometers Work

To understand infrared thermometers, you need to understand black body radiation. Everything warmer than absolute zero (read: pretty much everything) has molecules vibrating. Heat is the result of these vibrating molecules. They also generate infrared radiation, which is a spectrum of light that isn’t visible to the human eye.

Infrared light is perhaps most famous from technology like night-vision goggles, which sense infrared radiation and allow the wearer to see at night. Everything generates infrared radiation, and the hotter an object is, the more infrared radiation it will emit.

An infrared thermometer works by measuring the amount of infrared radiation being generated. Infrared thermometers use a lens to concentrate the infrared light onto a sensor called a thermopile, which converts the light into heat. That heat is turned into electricity, and the amount of electricity generated is used to measure the temperature of the object.

Ear drum thermometers work because the ear drum is about the same temperature as the inside of the body, but the ear drum itself is very sensitive and touching it would be painful. The infrared thermometer can instead measure the temperature of the eardrum from a short distance (less than an inch) away. Other infrared thermometers measure the infrared radiation coming off your body- specifically the temporal artery- to determine body temperature.

In the case of industrial or culinary thermometers, infrared thermometers measure the infrared light generated by a cooking surface or a fire. It’s a common misconception that the laser on these thermometers is what’s measuring the temperature, but actually these are only used to help aim the thermometer accurately.

Advantages of Infrared Thermometers

While they still aren’t as widespread as digital thermometers, infrared thermometers are very popular and becoming more common. Here are the biggest advantages of infrared thermometers:

  • No physical contact needed; very comfortable and very safe
  • Temperature readings are instant
  • Can be used with newborns, infants, children and adults
  • Very accurate readings

Disadvantages of Infrared Thermometers

Despite their impressive benefits, infrared thermometers are not perfect. Here are the biggest drawbacks of infrared thermometers:

  • They tend to be very expensive
  • Ear thermometers can be uncomfortable

Infrared thermometers are, generally, just as accurate as their digital counterparts and even easier to use, but the cost can make them impractical.

Why Infrared Thermometers Are Accurate

We’ve explained how forehead thermometers work, but we haven’t yet explained why they are accurate. In reality, infrared thermometers are not necessarily more accurate than digital thermometers- the main advantage they have over digital thermometers is their ease of use and the instant temperature readings they give.

That said, they aren’t any less accurate than digital thermometers either. That means that they have a lot of advantages over digital thermometers (faster temperature readings, more comfortable to use) without any real disadvantages.

The accuracy of forehead thermometers is due to science. A forehead thermometer is measuring the infrared radiation being generated by your body. Since there is a well-understood relationship between how hot an object is and how much infrared radiation it generates, using infrared radiation to measure heat is a very accurate method.

Forehead thermometers go a step further, though. Instead of just calculating heat from infrared radiation, they actually convert the infrared radiation back into heat, allowing them to measure the heat directly, even without touching your body. This is how they can be so accurate even without being in direct contact with the body.

Many people wonder how a forehead thermometer can accurately measure your internal body temperature when they aren’t being stuck in the mouth like a traditional thermometer. The answer is that forehead thermometers aren’t actually measuring the temperature on the skin of your forehead. They’re measuring the temperature of the blood in your temporal artery. Since they’re using infrared radiation to measure temperature, they can actually use measure the temperature of something below the surface. The temporal artery supplies blood to the brain, and since it’s a major artery the blood flow is quick. That, in turn, means the blood doesn’t have time to cool down after leaving the heart, and so it’s still at the same temperature as your internal body heat. Since the forehead thermometer is measuring the temperature of this blood, it’s able to accurately measure your internal body heat.

Why Your Forehead Thermometer is Inaccurate

If you’ve found your forehead thermometer to be inaccurate, there are several possible causes.

First, it’s possible your expectations might be too high. There are countless variables that can affect every individual’s body temperature, and no thermometer is going to be 100% accurate. Thermometers will measure slightly different temperatures all over your body- an oral thermometer will always give a slightly different reading than a forehead thermometer, because the temperature in your mouth is slightly different from the temperature in your temporal artery.

Different brands of thermometer will also give slightly different readings. This is not unique to forehead thermometers. If you buy two different brands of digital thermometers and take your temperature with both of them, in the same spot at the same time, there’s a good chance that each thermometer will give a slightly different temperature reading. The same is true for your forehead thermometers.

There are several reasons for these discrepancies. Different brands may use different manufacturers for their thermopile sensors, or different infrared lenses, different processors, etc. Even old-school analog thermometers with mercury will have these issues. If you’re worried that your forehead thermometer is inaccurate because it gives you a different temperature reading from other thermometers, you have nothing to worry about. This is perfectly normal and does not indicate that your thermometer is defective or inaccurate.

The most common reason for inaccurate readings with forehead thermometers is improper use. This means that if you get a truly inaccurate reading from your forehead thermometer, it’s almost certainly because you did not properly use it.

How to Use a Forehead Thermometer

First, make sure the forehead is dry. Running a fever often leads to sweating, and the sweat will interfere with the ability of the thermometer to take an accurate reading of the temperature in the temporal artery.

Once the forehead is dry. place the thermometer directly in the center of the forehead. Slowly, slide the thermometer across the forehead towards the top of the ear, keeping it in contact with the skin at all times. The temporal artery runs horizontally across the forehead, so you’re essentially following the path of the artery with the thermometer.

About two seconds after your start, you should have your temperature reading. As long as you have followed this procedure correctly, you should have an accurate temperature reading.

Always be sure to read the instructions that came with the thermometer, as some models do not require you to slide the thermometer and others may require a longer amount of time to generate the temperature reading.

As long as you’re following the instructions, you should not experience inaccurate readings with a forehead thermometer.


A forehead thermometer is every bit as accurate as a digital thermometer. With a forehead thermometer, you are able to quickly, accurately, and painlessly measure temperature. One of the chief disadvantages of oral thermometers is that many people, especially children, find oral thermometers to be very uncomfortable. This can make it difficult to take a persons temperature orally, since they often won’t sit still long enough for the thermometer to take their temperature.

In fact, the speed and comfort of the forehead thermometer might be it’s biggest selling point. It’s widely accepted that rectal thermometers are the most consistently accurate, but as with oral thermometers, these are very uncomfortable. Forehead thermometers don’t cause any discomfort and, while they may not be quite as accurate as a rectal thermometer, they come pretty close. Since they’re much easier to use and don’t sacrifice much accuracy, they’re likely the best choice for a thermometer.

Coronavirus took whole countries by storm this year. Most people were not well equipped for it, and it caused a lot of casualties. Entire nations have quarantined themselves in order to avoid the spread of the virus. Although people are doing all they can to keep it under control, the virus is still spreading. This may be caused by the fact that most people don’t know the symptoms. One of the most prevalent symptoms of the virus is fever. A thermometer gun is used in most checkpoints and airports to determine the temperatures of individuals. Other people use thermometer guns at home to ensure the safety of their families. If you are one of them, or if you are thinking of getting one for yourself or your family, here is a guide on how to use thermometer guns for coronavirus.

Symptoms of Coronavirus

Coronaviruses are a large virus family. They cause different illnesses in people, while others like the canine and feline coronavirus affect animals. The COVID-19 virus is short for Corona Virus Disease 2019, and it is said to be transmitted through the live animal market to people, and it is now transferred from person-to-person. COVID-19 has a 14-day quarantine period from the day of exposure, and a person who is released from quarantine after the 14 days cannot transmit the disease to others if they don’t have the symptoms of the disease.

COVID-19 is the official name for the illness caused by the current virus. It is a respiratory illness and can be transferred through person-to-person contact. The respiratory disease can have symptoms that mimic a common cold and can develop to more severe diseases like pneumonia.

Before going ahead and judging that anyone with a high fever has coronavirus, there are many other symptoms to keep in mind. The presence of these symptoms, combined with the fever, can be a sign of the virus.

Some of the symptoms associated with coronavirus are;

  • Fever
  • Shortness of breath
  • Coughing
  • Sore throat
  • Fatigue

These might sound like symptoms of normal flu so that you might get confused. Well, some of the ways to narrow it down can be if;

  • You were overseas in the past two weeks, and you have a respiratory illness
  • You have been in contact with someone who was recently overseas, or a person who is a confirmed case and you show signs of respiratory disease, whether you have a fever or not

Coronavirus or Flu?

As I said before, the symptoms of the virus can mimic those of a common cold or the flu, so how can you know whether it is a regular flu or if it is actually the virus?

The symptoms that are common with both the virus and flu or common cold are fatigue, sore throat, and coughing. The symptoms are similar because they are both respiratory diseases. One thing that sets the virus apart is the shortness of breath.

Another way to know whether it is the virus or not is to check for a runny nose. Sneezing and a runny nose are symptoms of the flu, so it is unlikely that it is the virus. Aches and pains will also accompany the flu.

Although there is a lot of overlap with the diseases, one distinguishing factor is the shortness of breath. This is because the virus attacks the lungs. Don’t panic yet, though, as this can be symptoms of an allergic attack. Before going to the doctor, make sure you have a combination of other symptoms like fever, dry cough, together with the shortness of breath.

How to Use Thermometer Guns for Coronavirus

Since the virus can be transmitted through inter-personal contact, ordinary thermometers cannot be used to check for a fever. This is where the thermometer gun comes in. The gun is a non-contact one that can let you take a person’s temperature with minimal to no contact. They use infrared sensors to measure the heat emitted by a body without touching the other person.

To use the thermometer, point it toward the person you want to measure and click on the trigger. The thermometer will measure the radiation emitted by the person and convert the readings into electricity, and this way, you get the readings.

For the thermometer to work effectively, it has to be held at precisely the correct distance from the surface to get accurate readings. Holding it too close will give higher temperatures while holding it too far gives lower temperatures.

Getting an accurate reading depends on the distance to spot ratio. The size and height of a person will determine how close or far from them, you should be to get the correct readings. Other factors should be taken into play too. For example, a person who has been running or doing physical exercises can give a higher reading even though they don’t have a fever.

The thermometers also have a +/-1 degree or a +/-2 degree accuracy. This means you can get a higher or lower reading on the thermometer. This can give a false reading, so it might be better to use a clinical thermometer.

In order to get accurate readings, always make sure to;

  • Know the distance-to-spot ratio of your thermometer. Also, make sure you are close enough to the person you want to measure so that it reads the surface you want to measure
  • Make sure the thermometer’s lens is clean, free from dust and scratches
  • Stay away from areas that emit high radiation as this can confuse the reading
  • Let the thermometer adjust to the temperature of the surrounding region before measuring the person

Is A Thermometer Gun Accurate?

The infrared thermometer is exact and consistent if used correctly. To get the best result, the distance between the object, in this case, is a person, and the thermometer should be smaller, and the laser has to be pointing toward the person.

There might be a problem; however, if it isn’t aimed at the person directly or if the distance between the two is great. The results can be compromised since the thermometer measures the radiation. A great distance might cause some of the radiation emitted to be released to the atmosphere, making you get false readings.

Safety Issues

The thermometer is safe to use when you take into account the mode of transmission of disease. Since coronavirus can be spread through person-to-person contact, this thermometer is the best and safest tool to use. This is because it can measure the temperature from a distance so you won’t have to touch the person, therefore, reducing the risk of the virus spreading

The thermometer gun is very suitable for use if you measure many people at a go, which is why it is used in airports and roadblocks. Since there is no contact between you and the people you measure, there is no risk of transmitting the virus among the people.

It might not be safe to use the thermometer on a person. The thermometer uses infrared radiation and lasers to gauge the temperatures, but this can cause skin and eye irritation if the laser hits the eye.

Safety Measures

With the virus running wild, there are some measures you can take to make sure you don’t contact it. These are some of the steps you should follow;

Wash your hands regularly

You should always make sure you wash your hands frequently and thoroughly with soap and water. You can also use an alcohol-based hand rub like a hand sanitizer. Doing this is necessary to kill viruses that can be on your hands. You might have been in contact with a person who has the infection, and washing or sanitizing your hands is the most effective way to kill the virus. Make sure you don’t eat or touch your face without washing your hands to avoid contamination.

Avoid crowded places

Crowded places are highly contagious places. You never know who can be contaminated, and the virus can spread that way quickly. To be on the safe side, keep a distance of at least 1 meter, 3 feet, between yourself and other people. This safety precaution should be taken very seriously, especially if the person near you is coughing or sneezing.

The distance is necessary because you should avoid liquid droplets that fall from a person’s nose or mouth whenever they cough or sneeze. If you are close to the person, there is a chance that you will breathe the droplets in, which might include the virus if the person has it.

Don’t touch your face

Avoid touching your nose, mouth, or eyes unless you clean your hands first. This is because our hands come into contact with so many surfaces. These surfaces hold loads of dirt, and once we touch them, all that dirt is transferred to our hands. The hands, once contaminated, can transfer the virus to the nose, eyes, and mouth. This way, the virus enters the body and proceeds to make you sick. Washing your hands regularly and not touching your face will help minimize the chances of that happening.

Practice respiratory hygiene

Practicing respiratory hygiene is not as hard as it sounds; in fact, it basic human decency. You need to make sure you plus anyone around follows these practices; always cover your mouth and nose with a bent elbow, handkerchief or tissue when coughing or sneezing and throw the tissue away immediately after use. You should do this to ensure no droplets are released into the air, protecting everyone from any respiratory diseases, not just COVID-19.

Seek medical care if you have a fever, dry cough, and difficulty breathing

If you notice any of the symptoms above and most importantly, if you have a combination of fever, difficulty breathing, and a cough, seek medical attention immediately. If you have a runny nose, it will probably be a cold or the flu, so just stay at home. But if your nose is dry and the other symptoms that might be symptoms of the virus, especially difficulty breathing and it is not an allergy, see a doctor. Make a call in advance so that the hospital is ready to accommodate you. Make sure you follow the directives issued by your local health authority.

The local authorities have all the current information on how to handle your situation. Calling in advance will help them prepare and direct you to a place that is equipped to handle the situation. It will also help in protecting you and prevent the spreading of the virus and other infections to other people around.

Stay informed

Make sure always to keep abreast of the latest developments about the virus. Listen and follow any advice issued by healthcare providers, local and national public health authorities. Follow their guidelines to ensure you protect yourself and others around you from COVID-19.  They are the ones who can give the best advice to what you should do to protect yourself, your family, and others.

Protection Measures for Those Who Have Been in Infected Areas

If you have traveled to an infected region in the past 14 days, there is a chance that you may have contracted the virus. So, what should you do to prevent spreading the virus even more, even if you have no symptoms?

  • Follow the above safety measures
  • If you start feeling unwell, no matter how mild the symptoms might seem, stay at home. The symptoms can include a headache and a slightly runny nose. Stay at home until you recover, making sure to avoid contact with others. Why should you stay at home? Going to the hospital or medical facilities with these symptoms will cause congestion in hospitals and increase contact with other people. Avoiding hospitals unless absolutely necessary will allow them to operate effectively and protect others from COVID-19 and other infections.
  • Avoid public places or public transportation.
  • Seek medical attention as fast as possible if you develop a fever, cough, or if you have difficulty breathing. These signs may be due to a severe condition or a respiratory infection. Call a healthcare facility in advance and make sure to inform the healthcare provider if you have traveled to an infected area or been in contact with someone who has. Doing this will give the healthcare provider to direct you to the correct facility. It will also help them to prevent the infection or other viruses from spreading.

If you have COVID-19

  • Isolate yourself even from people in your home and limit your contact with pets
  • Wear a facemask. Wear the mask if you are around other people and before entering a hospital or healthcare facility
  • Do not share personal household items like utensils and bedding
  • Wash any household items that are shared very thoroughly with soap and water
  • Clean and disinfect any surfaces that are touched frequently. If you cannot do it yourself, your healthcare provider should wait for as long as possible after you’ve left the room before coming in and cleaning it.

Common Myths about COVID-19

It cannot be transmitted in hot and humid areas

As yet, there has been no evidence to suggest the virus cannot be transmitted in hot areas. It can be transmitted anywhere, no matter the climate. You should adopt protective measures in whatever areas. Also, make sure to wash your hands regularly to kill any germs.

Cold weather cannot kill the new coronavirus

No matter the climate you are in, the normal body temperature for humans is 37 degrees Celsius, and the virus can survive in the human body. Practice protective and hygiene measures to be on the safe side.

Hand dryers are not effective in killing the virus

No matter what people say, hand dryers cannot kill the new coronavirus. Make sure always to clean your hands with soap and water or an alcohol-based hand rub and dry using paper towels, which you should discard immediately, or a hand dryer.

The thermometer gun is effective in detecting the virus

The most that the thermometer gun can do is detect a fever. As we said before, the thermometer gun measures temperature without actually touching the person. It can be effective if used properly. Make sure the distance between the thermometer and the surface to be measured is enough so that you don’t get a compromised reading.


Coronavirus has taken 2020 by storm and is causing a lot of discrimination and stigma in society. This is because people are inadequately informed about the virus, causing them to take drastic measures. Checkpoints and airports use thermometer guns to gauge whether a person has the symptoms attributed to the infection. The thermometers are used to detect high fevers, which can be a symptom of the virus. To use the thermometer gun, you need to aim it at the person you want to measure and click on the trigger. To make sure the thermometer gets accurate readings, ensure there is enough distance between the thermometer and the person, the lens is clear and free from scratches. Use the thermometer gun wisely to avoid causing unnecessary alarm and get help to those who might need them.

In simple terms, body temperature is an indicator of how well your body can generate heat and how well the body can get rid of the same heat. A rise or dip in body temperature is an indicator of a variety of health factors, and informs the next steps, including whether or not to see a doctor. A high temperature could signify a number of things, helping you determine whether you are simply overheated or are suffering from a fever. A lower body temperature than normal also help you determine factors like shock from trauma or an accident, and even hypothermia in extreme cases.

Whether it is for yourself, your kids or an adult you are taking care of, learning to take temperatures at home is important. This is especially so now that COVID-19 is making its way through the country. A fever is normally the first indicator of the symptoms, so it is necessary for everyone to have a thermometer kit around. Knowing how to use the kit to take your temperature helps you take the necessary steps towards getting help.

In this article, you will look at a few factors you need to know about measuring your body temperature, including the cases that should inform this step, the various methods you can use measure your temperature and a breakdown of each method so you can determine which one you should use on a case-by-case basis.

How to Measure Body Temperature:


  • Disinfect the thermometer doing alcohol wipes or a cotton wool dipped in alcohol. Let it dry then rinse it in water.
  • Place the thermometer inside the mouth. Put it under the tongue for a more accurate reading.
  • Close the mouth. Let the thermometer stay in place for at least one minute. A digital thermometer will give a beep once the recommended time is up.
  • Remove the thermometer and read the temperature.
  • Disinfect the thermometer and put it back in storage.


  • Disinfect the tip of the thermometer doing alcohol. Rinse with water once the alcohol has dried.
  • Lubricate the tip doing petroleum jelly. This ensures that insertion is painless.
  • Whether you are doing it to a baby or an adult, the knees need to be bent to ensure the anyou opens up fully.
  • Clean the pathway into the rectum. Presence of feces reduces the accuracy of results.
  • Insert up to one inch of the tip of the thermometer into the rectum.
  • Hold the thermometer in place around 1 minute, or until the thermometer gives a beep.
  • Remove the thermometer and read the temperature.


  • The ear has to be clean before this procedure. Ear wax affects the accuracy of the results. Take a Q-tip and gently clean the ear canal.
  • Make sure the tip of the thermometer is clean. Ensure that you do not use the same probe tip twice.
  • Pull back the ear gently so as to straighten the path from the outside of the ear to the ear drum.
  • Insert the thermometer gently into the ear canal until you reach the base.
  • Squeeze the button on the thermometer for one second.
  • Pull the thermometer back out of the ear and read the measurements.
  • Disinfect the thermometer and store it.


  • Remove any cloth barrier between the thermometer and the skin. For an adult, you might need to put the thermometer through the top of the cloth they are wearing.
  • Place the thermometer in the middle of the armpit while the person has their arm raised.
  • Hold the thermometer in place as the person gently lowers their arm back in place.
  • Leave the thermometer in the armpit for up to 1 minute.
  • Remove the thermometer and take note of the readings.
  • Disinfect the thermometer and store it.

Temporal Artery

  • Hold the thermometer over the forehead for a few seconds.
  • Remove the thermometer and read the temperature on the LCD display.
  • Disinfect and store the thermometer.

Why Measure Body Temperature

Your body temperatures are an indicator of many things, from your level of comfort in certain weather to the hormone levels in your body. Knowing the correct body temperature is an important gauge of where your health stands.

  • Fever: this is the most common reason why people measure the body temperature. A fever is an indicator of many health factors like infections, injury, and the effect of medicines on your body. An infection might increase your body temperature because your body is trying to fight it off, causing a fever. When you have an injury like burns or a heart attack, your body temperature is also going to be high, most likely due to the shock to your system. Underlying medical conditions like cancer and hyperthyroidism also raise your body temperatures because the body is trying to fight against the condition.
  • Hypothermia: While hypothermia comes with other indicators like shivering and confusion, the initial indicator is a low body temperature. Unknown to many, other factors like doing drugs, shock and infections can cause low body temperatures. When someone is in shock, maybe due to an accident, their body temperature can plummet sharply. The same thing happens to people with medical conditions like hypothyroidism and infections like sepsis. Measuring for low body temperature helps parents determine whether or not their newborns have an infection. Caregivers can also tell the medical condition of older adults by measuring for low temperatures.
  • Heatstroke: when you have a heatstroke, your body loses control of its temperature regulation, and therefore your temperatures keep rising. This can lead to shutdown of many organs, and may even lead to death. There are two types of heatstroke: classic heatstroke can build over a number of days and can happen even if one is not overly active or in an area that is too hot. When experiencing classic heatstroke, the body slowly loses the ability to sweat, a process that normally cools down the body to the average temperature range. Exertional heatstroke occurs when you work or exercise when temperatures are higher than usual. Even though you might sweat because of the exertion from work or exercise, the sweating is not enough to cool down the body, leading to a shutdown of your organs.

Facts About Body Temperature

There are two main types of body temperature and they vary according to the environment.

  • Core Temperature: your body’s core temperature is based on the temperature of the body’s mucous membrane. To establish the core temperature, you will need to insert a thermometer into the body, maybe through the esophagus or the urinary tract.
  • Surface Temperature: the surface temperature takes into account the level of heat inside the body and the temperature of the room. To get the surface temperature, you will use the thermometer on the surface of the skin e.g. under the armpit or forehead, or just inside your body e.g. rectum or ear.

The body has a range of temperatures under which normal functioning occurs. The average range for adults and children varies, and when temperature falls within this range, there should be no cause for concern.

For adults, a range of 97 F to 99 F (36°C to 37.5°C) is normal.

Newborns and children have a significantly higher range of temperature, from between 97.9 F to 100.4 F (36.6°C to 38°C).

Where to Measure Body Temperature

Axillary: the axillary method of measuring temperature is probably the most comfortable method because it is not invasive. Anyone can take the measurement without the risk of infecting the other party because the thermometer is placed under the armpit. Many healthcare professionals use this method when measuring the temperatures of both adults and children. If you use this method, keep in mind that the results will be a bit lower than the average temperature range because other factors like the temperature of the room affect the results. The normal temperature range for axillary measurement is between 94.46 F to 99.14 F for an adult.

Orally: oral temperature measurements are taken when the thermometer is placed inside the mouth, whether it is under the tongue (sublingual) or against the cheek (buccal). This method is preferred by parents and medical professionals when taking the temperature of young children. This method gives a normal range of 95.9 F to 99.5 F.

Tympanic: this measurement is given after inserting a thermometer into the ear canal. It is quick and very reliable, making it a popular method for use by physicians when measuring infants and young children. The normal temperature range when you use this method is between 95.9 F to 99.9 F.

Rectal: this method is considered the most reliable in gauging the body temperature. It is used both at home and by physicians to measure the temperature of children from birth onwards. However, it is a slightly invasive method that might make a few people queasy. Make sure you get instructions on how to do it correctly so as not to injure the patient. The good news is, if you use this method, you are guaranteed a high degree of precision. The normal temperature range doing the rectal method is between 97.8 F to 100.4 F.

Temporal Artery: this is the least invasive method and most comfortable for both the person measuring and the one being measured. It involves placing a digital thermometer near or on the forehead and getting the readings from a digital display. It has a high degree of variation, which has put into question the accuracy of the measurements. The normal temperature range doing this method is 95.9 F to 99.3 F.

Types of Thermometers

Gone are the days of mercury thermometers. While you might find a few on the market, keep away from them whether you are taking the temperature for a child or an adult. Mercury is toxic and could have adverse effects due to poisoning.

Digital thermometers are popular because they are easy to use. They eliminate the hassle of having to read a scale in order to gauge the temperature, something that could lead to inaccurate readings especially if you are not a professional. Digital thermometers display the readings on a small LCD screen.

Infrared technology is used in many thermometers. This protects the people the thermometer is used on from allergies due to interaction with chemicals. Infrared thermometer is commonly used in temporal artery this thermometers which have two sensors. One sensor takes the highest temperature while the other records the temperature of the room. The difference between the values gives the body temperature.

Disposable thermometers are designed for only one use. Disposable thermometers come in handy and are best used to measure temperature doing the axillary or oral method.

Pacifier thermometers and plastic strips are a type that has grown in popularity in recent times. Their accuracy is not the best and many professionals advise against their use. If you are unsure about which type of thermometer to get for use at home, the best thing is to ask a professional like your child’s pediatrician or your local pharmacist.


Knowing how to measure body temperatures is a necessary skill. It helps you decide whether you need to take action and get to the hospital, or look for home remedies that will help lower the temperature to acceptable levels. If used well, this skill can be life-saving, whether you are taking care of a child or an adult who has been in an accident or experienced trauma.

There are many options to choose from when measuring body temperature: you can decide to do the temporal method or axillary measure when you are dealing with someone you are not comfortable with. The oral and rectal methods give more accurate results, and they can be used for infants and young children.

Make sure to disinfect the thermometer before and after every use. If you use disposable ones, make sure you dispose of them where children will not be tempted to play with them.

If you are not a doctor, make sure that you consult one if you notice the body temperature of the person you just measured is lower or higher than the normal range. Now that you know the range each method gives, you are better placed to make good judgment as to when to consult a physician.

Concern increases daily with various questions arising about the Types of temperature sensors in order to make the best choices. There’s a truckload of things you need to know about this various types of sensors, their applications, pros and cons, and affordability. This article aims to equip you with all the knowledge you seek. Stay glued and keep reading to learn more.

It’s quite plain to delve into the subject matter without an understanding of the subject matter itself. This makes it necessary to exhaustively examine what Temperature sensors are. From the name “temperature sensors”, it can be deduced that this equipment is used for measurements, particularly temperature related measurements.

Temperature sensor is an equipment that measures temperature through an electrical signal through a thermocouple or alternatively an RTD. A Thermocouple on the other hand is manufactured from two metals which are dissimilar in nature and produce in commensurate proportion to temperature changes, voltage that is electric in nature.

Without Undue prejudice, it should be kept at heart that one of the most widely evaluated parameter is temperature as it cuts across a wide range of laboratories and Industries. Exact and precise measurements are very cogent determinants of success and are required for a range of applications which include laboratory research, study of geology, study of electronic components, and most importantly medical tests.

What is Thermocouple and How Does it Work?

As earlier mentioned, a thermocouple is manufactured from two metal wires which are dissimilar. However, these dissimilar wires are attached to each other on one end to serve as a hot measuring junction while the other end popularly known as cold reference junction is connected to an electronic digital indicator. Based on this structure, the Thermocouple generates signal of measurement in response to temperature differences between the hot junction and cold junction and not in response to actual temperature as expected.

However, to induce accuracy, a tiny ambient sensor is attached in the electronic digital indicator (close to the cold junction) to be added by the electronic digital indicator to the thermocouple temperature difference in order to calculate and display the actual temperature on screen.

What is an RTD?

Fully known as Resistor Temperature Detector. All electrical conducting devices to a certain degree, whether greater or lesser have resistance to the electricity flow. This resistance to electric voltage varies based on the Conductor’s temperature which can be evaluated to match a specific temperature. Also, the material which is commonly utilized in an RTD is platinum as a result of its stability, purity over a wide temperature range.

With the information above, it can be deduced that just two  copper wires are required to connect an RTD to a circuit. Nevertheless, these wires are susceptible to resistance changes as a result of environment’s temperature. This makes it important  for an extra wire to be built into many RTDs to augment and aid the digital controller’s accuracy for all the variations.

Well, since you’re now intimate with a bit of the technical scope of a temperature sensor alongside its composition and functions. We shall exhaustively examine the various types of sensors. The Thermometer is the most common and widely utilized kind of temperature sensor and used for solid, liquid and gas Temperature measurement. It’s wide use stems from its slight chances of not being so accurate. As a result, it is used for non-scientific purposes.

The types of Temperature sensors are distinguished from each other based on sensing capacity over their application range. The types of Temperature Sensors are:

Types of Temperature Sensor

  1. Thermocouples
  2. Resistor Temperature Detectors(RTD)
  3. Thermistors
  4. Thermometers
  5. Semiconductors
  6. Infrared sensors

Surprised the Thermocouples and Resistor Temperature Detectors surfaced as part of the much anticipated types of temperature sensors. What we examined earlier was an overview of it’s operation. Now, we shall consider these types of sensors exhaustively to give you tips on how to pick the best amongst others.

1. Thermocouples

Thermocouple sensor, usually abbreviated as TC is a very desirable temperature sensor. These type of temperature sensors are affordable, durable and used in a wide range of applications such as Industrial, consumer and automotive. Thermocouples are independently powered, operate over a wide range of temperature with quick response duration, and do not require excitation. Usually, thermocouples consist of two distinct metals known as Opened and closed metals. These metals work on the thermo electric effect principle to cause a seebeck effect( a situation in which distinction in temperature of two dissimilar conductors causes a difference in voltage between two substances and the voltage difference can be measured to calculate temperature).

Despite the overview done in the introductory paragraph, there are numerous kinds of thermocouples that are produced from a wide variety of materials which induces and aids distinct range of temperature and distinct levels of sensitivity which we didn’t mention in the introduction. These distinct types have letter designations for easy identification and effective enumeration.

For a detailed understanding, these types shall be extrapolated with their different code type, conductors alloys, sensing temperature and sensitivity. The most commonly used thermocouple is the K type with Nickel Chromium or Nickel Aluminium conductor alloys, -180 to 1300°C sensing temperature and 41°C sensitivity . Others are the E type( with Nickel Chromium or constantan conductor alloys, -40 to 900°C sensing temperature and 68°C sensitivity), J type (with Iron or Constantan conductors alloys, -180° to 800°C sensing temperature, 55°C sensitivity), N type (with Nicrosil or Nisil conductor alloys, -270°C to 1300°C and 39°C sensitivity), T type (with Copper or Constantan conductors, -250 to 400°C sensing temperature, 43°C sensitivity), R/S type (with Copper or Copper Nickel Compensating Conductor alloys, -50 to 1750°C sensing temperature and 10°C sensitivity) and the B type (with platinum rhodium conductor alloys, 0 to 1820°C sensing temperature and 10°C sensitivity). Without prejudice, the J and T types also enjoy a wide range of utilisation and are available in ready-made forms.

It is known that for every great equipment, there are peculiar features and complimentary setbacks to performance. The thermocouple is non linear, that is, the voltage output is not linear to temperature itself and conversion of voltage output to temperature requires mathematical calculations.

This feature has proven to be a disadvantage of thermocouples. This is as a result of the small voltage output which makes measurement an arduous task as precise amplification vulnerability to external noise over lengthy wires and cold junction( where the wires meet) is required. This creates the seebeck effect earlier mentioned.

Not to worry, Maxim integrated offers solutions to this with its digital output thermocouples which include the MAX 31855 and MAX 31856. These aid signal conditioning by blending a high-resolution analog to digital converter (ADC), low noise precision gain stage, and cold junction compensation sensor. These equipment aid producers and designers of thermocouple circuits to offer detailed, accurate and practical solutions to signal conditioning in a tiny affordable package. Interestingly, these devices work with many of the popular types of thermocouples earlier extrapolated.

2. Resistor Temperature Detector

RTD sensors are also widely used and one of the most accurate types of temperature sensors.  In a Resistance Temperature Detector, the resistance is proportional to the temperature. As a change in temperature occurs, the resistance of any metal changes as well. The distinctions in resistance is the major determinant by which RTD sensors measure temperature. The Resistor Temperature Detector is produced from copper metals, platinum and nickel and has a quite wide range of temperature measurement  capabilities. It can be used to ascertain the range between -270°C to +850°C.

The most widely utilized material is platinum and Resistance Temperature Detectors made from this material are referred to as Platinum RTDs (also known as PRTDs). These RTDs often have at their disposal a 100 ohms and 1000 ohms resistance at 0°C which are referred to mostly as PT100 and PT1000 respectively.

The rationale behind the use of Platinum RTDs is not far fetched as they offer a direct response to changes in temperature, they are consistently stable and accurate, provide recurring responses and possess a wide temperature range. This accuracy and frequency facilitates the use of RTDs in precision applications.

However, an external current source is required for RTDs to function properly. Nevertheless, the current source usually generate heat in the resistive element subsequently orchestrating error in measurement of temperature. The error could be calculated via this formula:

Delta T = P*S

Where, T is temperature, P is I squared power generated and S is a Degree C or mill watt.

This is because resistor temperature Detector elements have a greater thermal mass and respond less effectively to temperature changes compared to thermocouples. This makes signal conditioning and flow of excitation current important in resistor temperature Detectors . Once the current which flows through the resistor temperature Detector is known, the resistance can be calculated.

There are different configurations for measuring temperature in resistor temperature Detectors after the current error has been ascertained. These are the two-wire, three-wire and four-wire options. The two wired option is easy to design and implement. The current is coerced through the  resistor temperature Detector to accurately ascertain the resulting voltage. It is useful when lead length is so short that resistance doesn’t have a significant effect on accuracy of the measurement.

The three-wired option shares certain similarity with the two wired method, however the third wire is a compensation for the lead resistance as it adds a resistor temperature Detector probe that can contain the excitation current. The Four-wired which is the most accurate completely provides compensation for the lead resistance. The current is coerced on just one set of the wires while voltage is sensed effectively by the other set of wires.

3. Thermistors

Another notable type of temperature sensor is a thermistor which is similar to Resistor Temperature Detectors as changes in temperature causes ascertainable changes in resistance. Thermistors are quite affordable, easy to use with speedy adaptability. However, most Thermistors are produced in two wire configurations and less accurate than Resistor Temperature Detectors.

Thermistors are usually produced from materials such as polymer or ceramics which are made from manganese and oxides of nickel. This makes them vulnerable to damages.

Although the thermistor sensor is less accurate compared to a Resistor Temperature Detector, it offers an higher level of sensitivity compared to resistor temperature Detectors. Also, most thermistors possess a Negative Temperature Coefficient (NTC) which is used for application of temperature. A Negative Temperature Coefficient’s temperature increases as the resistance  decreases. This type of sensors require an important correction to accurately interpret data as they possess an absolutely non-linear temperature resistance relationship.

Also, the common approach to use a thermistor is where a thermistor and a fixed value resistor form a voltage divider with an output digitized by a digital converter (ADC).

4. Thermometers

Thermometers enjoy a wide range of application especially in the medical line. A lot of persons today know the different types of thermometers and how they work coupled with it’s inclusion in basic school curriculum.

Thermometers are devices used to measure temperature of solids, liquids, or gases. The word thermometer has its origin from a couple of words: thermo which connotes heat and meter which connotes measurement.

The thermometer consists of a liquid, which is either mercury or alcohol in its glass. Its volume is linearly proportional to the temperature. That is, the thermometer’s volume increases when there is a corresponding increase in temperature.

When this liquid is boiled, it causes an expansion inside the thermometer’s small tube. To give accurate readings, the thermometer has a calibrated scale with numbers marked alongside the glass tube to infer the temperature when the mercury line is at that point. Temperature in thermometers is recorded in Fahrenheit, Celsius or Celsius scales respectively. This makes it necessary to take note of the scale in which the thermometer is calibrated before commencing measurements.

5. Semiconductor sensors

Semiconductor sensors are devices that come in form of ICs and are majorly known as IC temperature sensor. There are two distinct types (without undue prejudice to others) of Semi Conductor sensors which are Local Temperature sensors and remote digital temperature sensor. Local temperature sensors are ICs which make use of physical transistor properties to measure their temperature while Remote digital temperature sensors quantify the temperature of an external transistor.

Moreover, local temperature sensors can utilize either analog or digital outputs. Analog outputs could be either voltage or current. Local Temperature sensors discern temperature on printed circuit boards or the ambient air surrounding it. A good example of very handy local temperature sensor which has a very flexible application range is the Max 31875.

On the other hand, remote digital temperature sensors function in a similar manner with local temperature sensors by making use of a transistor’s physical properties. The distinction lies in the location of the transistor which is far away from the sensor chip. Also, some microprocessor have an inbuilt bipolar sensing transistor to measure target IC’s temperature.

Other types include the diode temperature sensors and resistance output silicon temperature sensor. The silicon diode temperature sensors have been specifically optimised for the cryogenic range of temperature. They are also devices with linear configuration where the diode’s conductivity rises in a linear progression in the low cryogenic regions. In recent times, present semi conductor temperature sensors offer a high linearity and a corresponding accuracy over an operating range of about 55°C to +150°C. Regardless, the most common and popularly validated of these kind of sensors are AD590 and LM35.

6. IR sensor

These sensors are commonly referred to as IR sensors for convenience. They are actually Infrared sensors and are electronic devices which can be utilized to infer certain readings and qualities of its present environs by either emission or detection of Infrared radiation. These sensors are peculiar sensors and do not require contact. For instance, simply place your Infrared sensor on your table without any prior or subsequent contact, the sensor detects the desk’s temperature regardless utilizing its radiation feature.

Infrared sensors are classified into two types namely Quantum Infrared sensors and thermal infrared sensors and each has its peculiarities to suit whatever process required.

What Are The Things to Look Out For When Making a Selection Amongst The Types of Temperature Sensors?

Asides detailed and technical explanations given about the temperature sensors. You could still be left in a dilemma concerning the best one for you. This takes us a step further to examine factors you need to look out for before making a purchase of your desired temperature sensor. It is important to know that the application is the overall determinant. Hence, the factors to be examined would serve as a guide to determine which would best suit a particular application. These factors are extrapolated as follows:

Temperature Range

This should be your first consideration when making a choice amongst the various types of sensors for a peculiar application. The various types of sensors are more effective with different ranges. For instance, Negative Temperature Coefficient Thermistors are more effective when applied from -50°C to +250°C. Hence, it is suitable for a wide range of application.

Thermocouples are also less accurate at relatively lower temperatures but are able to measure temperatures as much as 2000°C. Resistor Temperature Detectors also work within a wide temperature range but lower than the thermocouple’s unlike Semi Conductor sensors which possess a very restricted temperature range.


Accuracy is also a very cogent factor which must be considered. For instance, thermocouples are frequently inaccurate compared to Resistor temperature Detectors and thermistor temperature probe even though they cost less.

Negative Temperature Coefficient Thermistors and thermistor probes are the most accurate between -50°C and +150°C. If encapsulated in a glass, they could be extremely accurate at 250°C. However, this thermistors are still not as accurate as the Resistor Temperature detectors and need a great deal of correction of data to interpret the temperature.

Resistor Temperature Detectors provide accurate and reoccurring measurements. If your application requires a great deal of accuracy, these sensors should be your pick amongst others.


Speed might be important for your application. This would make a Resistor Temperature detector less useful for you. Although it is very accurate, it is slower and requires and excitation and signal conditioning to properly function. A thermocouple, thermistor or thermometer would be more preferable.


The length of your operation must be put into maximal consideration. This takes a toll on your choice of temperature sensors as these sensors could become less effective and efficient overtime subject to their configuration, packaging, production, and quality of materials utilized for their construction.

For instance, over the course of a year, a thermistor can change by 0.02°C to 0.2°C subject to the presence or absence hermetical seal. A thermocouple can also transform by 1°C to 2°C as the year goes on. This makes this sensors preferable to other sensors as the change is relatively smaller.

Packaging or Style

The manner in which a temperature sensor is packaged differs based on the application for which it is required. Threaded studs are suitable for general purpose applications while closed tubes such as thermometers are well suited to liquid measurements application.

Moreover, If you prefer your sensors handy and easy to carry about, a clinical  thermometer or Negative Temperature Coefficient Thermistors would be okay. Your best bet is the Semi Conductor sensor which comes in extremely minute packages making mobility easier and efficient for you.

Resistance to Noise

You wouldn’t want your operation delayed for failing to equip yourself well, would you? Before selection, you should check the temperature sensors resistance to noise and how effective it can be in your target location. Negative Temperature Coefficient Thermistors have proven to have an high level of resistance at the initial switch which makes them resistant to lead resistance and electrical noise. Thermocouples are also resistant to lead resistance but are vulnerable to electrical noise due to their small output signal.

I can bet you know best the right choices to make after reading this. You can now explore various applications with the types of temperature sensors exhaustively discussed.

Battery testing is one of the easiest things to do today, especially when there are equipment to aid the process. There are different kinds of batteries, and each of them requires different testing processes to know if they are still useful or not. Here, we are interested in how to test a AA battery; of course, it would be quite easy to do that using the drop test, but there are other ways too.

Simple Drop Test

AA batteries as known as penlite battery are cylindrical dry batteries used for a number of purposes. For instance, they are used for small devices like remotes, radios, toys, and small lamps. Battery life is almost perfect at the outset, but as time goes by, they run dry till they become useless.

As an alkaline battery, the drop test actually works on them. What you only have to do is drop them and see if they bounce or not; if they do, the battery is bad; if not, the battery is still good.

How to Perform a Drop Test For AA Batteries

There are three steps involved in this drop test for double A batteries. They include;

Hold the Batteries Vertically Downwards

Since AA batteries are small in size, it is very possible to hold them downwards. This means there should be a distance between the batteries and the ground level. The perfect distance to hold the battery above the ground is 5.0 to 7.5 cm; once you do this, you should have the drop test done seamlessly. For AA and AAA battery, the positive sides should face upward and the negative sides downward.

The reason why you are holding the battery in that position is that there is a possible buildup of zinc oxide. This happens mostly in alkaline batteries. When zinc oxide builds up in the battery, it gets bouncier – which accurately tells that the battery is bad and ready for replacement.

See What Happens

After you must have held the batteries in position, try to drop them and see what happens when they drop. There are only two things that could happen – bounce or not bounce. If it drops without bouncing and rolls sideward, then the battery is good and fresh; if it drops and bounces a couple of times before it eventually rolls sideward, then the battery is bad. This behavior differentiates between a new and an old battery.

However, there is something you should know – the bouncing battery could still be working; this doesn’t mean it is entirely dead, rather getting old. As a matter of fact, you would see a reduction in its performance on any device used on.

Make a Comparison

Just in case you need more clarity on the test you have just performed, an additional test is provided. Here, you would need an actually dead battery to compare. You would drop the dead battery and the AA battery to be tested at the same time; record your observations. You would notice that the dead battery would bounce even better than the tested one. This clearly shows that bounces vary from one battery to another depending on the condition.

The drop test is a very simple, yet effective test that can be performed almost anywhere. This test is great, especially when you have a collection of batteries that you are not sure if they are dead, fresh or old. So, you are subjected to a bounce/drop test; you wouldn’t even need to spend anything to get the batteries tested.

Asides the bounce/drop test, the two other ways to test a AA battery is using a Voltmeter and a Multimeter. The equipment is also very effective and there are methods for their usage.

Using A Voltmeter Meter To Test AA Batteries

Voltmeter is used to calculate the amount of voltage in a device or battery. Although, you need to get the device in order to do the test. A voltmeter varies in price; it ranges between cheap to expensive depending on the model/make.

Using a voltmeter to test battery is fast and super easy to do. In fact, you don’t need to perform a drop test before you know if a battery is good or bad. There are readings on a voltmeter that would give volt measurements of such a battery or device. However, while using a voltmeter, ensure the connection is stable or else, it wouldn’t read the right measurement or scal.

Below are steps used to test AA batteries with a voltmeter.

  • Locate Terminals

The first thing you need to do if you are using a voltmeter on a battery is to locate the terminals. There are two terminals on every battery – the positive and the negative. Now, because you need an exact, accurate measurement of the charge on the battery, you need to align the terminals with the voltmeter. Majority of these aa batteries have a sign marked on their two ends stating the positive and the negative side. In the absence of the marked signs, the negative terminal is flat while the positive terminal protrudes outward. After locating terminals, you can then proceed to the next step.

  • Set to DC Setting

A voltmeter works in two modes – AC and DC setting. AC, also called Alternate current is mostly used for higher devices while DC, also called Direct current is used by all batteries. Before you start, check if the voltmeter is not on AC; rather, it should be on DC. If it is on AC, chances are that the whole test process would be futile or readings would be wrong.

There is a knob on the voltmeter which can be used to switch in between currents. Once, it is in DC, readings can be taken when the test is being conducted.

As aforementioned, voltmeters vary in model/make; therefore, some would require you to choose a max testing level. Most of the time, the minimum testing level/setting is 20 volts.

  • Connect Leads to terminals

This is the point where you introduce your voltmeter to the battery about to be tested. Every voltmeter comes with leads which will be connected to devices or batteries for readings. Without these leads, it is impossible to determine volts. There are two main leads on a voltmeter – positive red lead and negative black lead.

What you would do is: connect the positive red lead to the positive battery terminal and the negative black lead to the negative battery terminal. The moment you do this, the voltmeter starts taking readings. However, there is nothing hazardous going to happen if you mix up the leads with the terminals; only that readings would be negative.

  • Hold the Leads in place

Those leads weren’t designed to stay stuck in a position; rather be held in place. The moment the connection becomes unstable, readings may be inaccurate. Now, the voltmeter would start reading immediately the connection is made, but it could fluctuate due to external factors. So, what you have to do is hold the positive and negative leads connected to the two terminals in place till a particular value becomes constant. This value determines the condition of an aa battery, i.e., fresh or old. A fresh AA battery has 1.5 volts – anything less means it is either old or dead.

  • Do a Load test with AA battery

Once you have readings of the battery already, you may decide to subject it to a load test. This is a further way to test the efficiency of the battery. A load test helps in measuring a battery’s power when it is put to use. Before you do this, there is something else you must do – since AA battery has 1.5 volts, set the voltage dial at the mark. When you do that, place the battery on the loader, i.e., red probe on positive terminal and the black probe on negative terminal, then wait for readings. Anything between 1.0 to 1.49 is great; anything less than 1.0 is old or dead depending on the value.

  • Perform a Simple Reading

Finally, see how the battery works with a tester. The tester performs a simple reading on the battery, such that volt is displayed for you to see. It is a very easy device to use, and all you need is to open the slide and insert the battery. It is an adjustable tester suitable for all kinds of batteries, including AA batteries. Only make sure the positive terminal of the battery is touching the slide, or else it won’t take any readings.

From these steps above, you obviously don’t need much technical know-how to use a voltmeter, especially for testing a battery. As long as you can locate the terminals, connect leads to the terminals and wait for readings, then you are good to go.

Using A Multimeter To Test AA Batteries

Similar to a voltmeter, a multimeter can also be used to test for the charge in a battery or device. It is the perfect alternative, only that it measures all kinds of charges. A voltmeter measures volt in DC and AC; on the other hand, a multimeter measures amps (current), volts (voltage) and ohms (resistance). Thus, it does more than a voltmeter.

A multimeter can be used on AA batteries in the absence of a voltmeter. The steps are somewhat alike, only that you need to change the dial for a volt measurement.

Briefly, this is how to use a multimeter on AA battery:

  • Identify parts of the multimeter

It has an exotic look which makes it even necessary to check out its parts. There are quite a number of features you should get yourself familiar with before you make a move to testing a battery. For instance, the dial of the multimeter takes the read for your device; the selector switch or knob is to adjust settings like changing functions from ohms to volts or amps to volts; the test leads/probes are used for testing and measuring – they are connected to the positive and negative ends of the battery; fuse or battery compartment are power sources for the multimeter.

  • Change function to Volts

For a new or used multimeter, possibilities are that the function is either off or another reading. It is your responsibility to change to volts, so accurate measurements could be taken. You can easily change the function with the help of a selector switch or knob. Each turning is marked by a “click” sound.

  • Set meter at 1.5V for AA battery

Now, since you will be testing a aa battery, you may as well proceed to set a volt level on the multimeter. The volt level would have to be the highest known for that device or battery. For instance, the max volt level for aa battery is 1.5V; hence, the meter should be set at that limit, so that it can read anything below or up to that.

  • Insert Probes

Next thing to do is insert the probes in its compartment. There is a positive red and negative black probe to be used. Similarly, there are two small holes on a multimeter where you would have to insert the ends of these probes into. The positive goes into the red hole while the negative goes into the black hole. Once you do this, you are ready for battery testing.

  • Test on Battery

To the main thing on the agenda, test the probes on the AA battery and see what happens. Connect the positive probe to the positive end and the negative probe to the negative end of the battery. Make sure you hold in place for few seconds for an accurate reading.

  • Read voltage scales

In about a few seconds, there should be a constant value displayed on the multimeter. This value is the actual charge on the battery; it shouldn’t be more than 1.5V. The amount of charge determines the life of the battery, i.e., dead or old or alive.


It is easier to test aa battery than any other kind of battery because it is simple and smaller in size. While there are simpler tests to prove battery life – drop test, there are also effective tests to prove and show the charge on a battery – voltmeter and multimeter test. Whatever test you carry out; it would certainly give an accurate description of a battery’s behavior.

For many of us, infrared thermometers are a new thing. While using one may seem pretty straightforward, the reality is that if you don’t use it correctly, you won’t get an accurate reading. You also won’t get an accurate reading if you’re using the wrong kind of infrared thermometer.

If you’ve just received your new infrared thermometer, or you’re doing your research before purchasing one, you need to know how to use it once you get it. You also need to be sure and purchase the best infrared thermometer, since different kinds are made for different purposes.

How do Thermometers Work?

In order to understand how to properly use a thermometer, it’s helpful to know how thermometers work, first. All thermometers are tools for measuring heat. All of them, no matter the type, rely on a small amount of a substance that reacts to heat in specific ways to measure temperature.

Old-school mercury thermometers, for instance, rely on the expansion of mercury when exposed to heat. Because mercury responds to heat in a predictable way, it’s easy to use it as a way to measure temperature.

The reason why this works is that heat is actually a form of energy. At the atomic level, heat is movement. If you were to take a hot object and put it under a microscope next to a cold object, you’d see that the atoms in the hot object are moving around a lot more than the ones in the cold object.

Heat also works like air- it wants to move from areas of high pressure to low pressure. To understand this, you need to remember that “cold” is really just the absence of heat- you can’t actually measure how cold something is, you can only measure how much heat something has. When something is cold, it has very little heat.

If you put a cold object next to a hot one, the heat wants to even out by warming up the cold object. The rate at which this happens depends on what those objects are made of, because some materials conduct heat better than others. Metal is more conductive than wood, and silicon and rubber materials conduct heat so poorly that they can be used as insulators.

For a long time, most thermometers used metal to measure heat. Mercury is, in fact, a metal. It’s simply metal that is liquid at normal temperatures, which makes it very responsive to heat. Other thermometers, including the ones that come built in to a lot of grills, cheap oven thermometers, and the ones that come in your Thanksgiving turkey, are bimetal thermometers.

These thermometers use two different metal strips- often steel and copper- that are attached to each other and conduct heat at different rates. As they’re heated, the combined metal strips will bend in one direction, and they’ll bend in the other direction when they’re cooled. These are popular because they’re cheap, but they’re also very inaccurate.

Thermometers that rely on metals responding to heat to measure a temperature are imprecise and bimetal thermometers especially can be off by 5-10 degrees. They also take a relatively long time to give you a temperature reading. This why professionals in fields that require regular temperature readings- chefs and doctors- almost always prefer digital thermometers.

Most digital thermometers use a sensor called a thermoresistor. These are usually a small piece of glass with two wires attached. As the glass heats up, it’s resistance to the flow of electricity changes. A small computer in the thermometer can detect that change, and uses it to calculate a much more accurate temperature reading. What’s more, these are often instantaneous readings.

How Are Infrared Thermometers Different?

You’ll often see infrared thermometers labeled as “digital infrared thermometers,” which can be confusing because digital thermometers are not the same thing as infrared thermometers. Infrared thermometers are indeed digital, meaning that they use a computer to calculate temperature, but they don’t function the same way as other digital thermometers.

All other types of thermometers have to be in direct contact in order to measure a temperature. For medical thermometers, that means they have to be touching the body- more accurately, they have to be in physical contact with the interior of the body, either in the mouth or in the rectum- to get an accurate reading of body temperature. For a meat thermometer, it has to be in physical contact with the interior of the meat, which is why they look like large needles.

What makes infrared thermometers so unique is that they can measure temperature from a distance. Exactly what that distance is will depend on the brand and type of thermometer, but it gives them a distinct advantage in many situations. If you have to take your child’s temperature, an infrared thermometer makes for a much more pleasant experience than a digital one.

Let’s go back to what heat is- it’s energy that’s manifested in the movement of atoms. As those atoms move around, they generate infrared radiation. Infrared radiation is light, it’s just not light that you and I can see. Everything generates infrared light, and the amount of infrared light that something generates varies based on how hot it is.

You’ve probably seen infrared in action before- it’s how night vision goggles and cameras work. You’ll see that technology used by everyone from nature documentary crews to the military. An infrared thermometer measures the amount of infrared light that something is generating.

How Do Infrared Thermometers Work?

The way that infrared thermometers work isn’t too different from the way that most digital thermometers work, the only major difference is that they are able to measure the temperature from a distance.

Infrared thermometers have a special lens that focuses infrared light onto a special sensor called a thermopile. The thermopile converts that light into heat, and then that heat is converted into electricity. The amount of electricity being generated is then used to calculate the temperature.

This gives you a very accurate temperature reading and the results, like with most digital thermometers, can be nearly instant. The best part is that you can take that temperature reading from a distance. If you’re trying to figure out how hot your grill is, you can get a reading from several feet away.

Different Types of Infrared Thermometer

Infrared thermometers are used in almost any situation that requires temperature readings. They’re especially popular in industrial settings where the ability to take an accurate temperature reading from a distance is a major safety concern.

For most people, though, there are only two kinds of infrared thermometer you need to know about: medical infrared thermometers and gun-style infrared thermometers.

Gun-Style or Digital Laser Thermometers

A quick look at one of these thermometers makes it obvious why they’re called “gun-style”. These are the most common infrared thermometers, because they have a lot of uses. They can be used in scientific and industrial settings, and they also have a lot of home uses.

These can measure the temperature of a skillet on the stove or of the surface of your grill, which can make your cooking much better. They’re designed to measure very high temperatures from a safe distance, but they can measure a wide temperature range. This one can measure temperatures as low as 58 degrees, and as high as 1112 degrees. They’re excellent for cooking, auto repair, and home repair needs.

The only downside to these thermometers is that they can only measure the surface temperature of an object. It’s why you still need traditional meat thermometers for cooking- if you have to measure the interior temperature of an object, these thermometers just aren’t useful.

Medical or Forehead Infrared Thermometers

Though they’re often called forehead thermometers, that name is misleading since infrared thermometers don’t always work that way. You may remember from your own doctors visits that your temperature was often taken through your ear.

That was an infrared thermometer. The ear drum is the same temperature as the inside of your body, but it’s an incredible delicate organ. Actually touching it with a thermometer would be very painful, so an infrared thermometer takes the temperature from a little under an inch away from it.

Forehead thermometers work by measuring the temperature of the blood in your temporal artery. Like the eardrum, this blood is the same temperature as the inside of your body even though it’s very close to the surface. Also like the eardrum, it would be impossible to get a thermometer into direct contact with it. Most models of medical infrared thermometers sold for home use can be used as both an ear and forehead thermometer.

Medical infrared thermometers can’t measure as wide a range of temperatures as the gun-style thermometers, and they have to be held much closer to take a temperature, but that’s because they are measuring a very small object and they don’t need as much range.

How to Use an Infrared Thermometer

As you might have guessed by now, how you use an infrared thermometer will depend on which type of infrared thermometer you’re trying to use. While they operate along the same principle, actually using the different types of thermometer is very different.

Gun-style Thermometers

These thermometers have a laser on them. It’s commonly thought that this laser is what’s measuring the temperature, but as we’ve already seen the thermometer is measuring infrared light, not laser light. The laser is only there to help you aim the thermometer accurately.

This means you need to know how the laser is mounted on the thermometer. Some models place it above the infrared lens, while others place it below. Depending on how the laser is placed, you’ll actually be measuring the temperature of the spot just below or above the laser, not the spot where you can see the laser dot on the surface.

Using these thermometers is fairly straightforward. Point it at whatever object you want to take the temperature of, and pull the trigger. The trigger is the “on/off” switch, pulling it turns the thermometer on, letting it go turns it off. As long as you’re holding down the trigger, the thermometer will take continuously updated temperature readings.

Just remember that if you need to take the temperature of a relatively small object you’ll want to aim the laser slightly above or below your target. For instance, if you want to take the temperature of a grill grate, you’ll want to aim the laser between the grates at the coals or burners so that the lens is actually measuring the infrared light from the grate.

Medical Thermometers

There are two ways to use a medical infrared thermometer- in the ear, and on the forehead. For an ear thermometer, you first need to check the ear for wax. Too much ear wax and the thermometer won’t be able to get a good reading. Also note that, if the ear is infected, you should not use an ear thermometer.

Pull the ear up and back (or down and back for babies under 12 months old), and gently insert the thermometer. Don’t force it, and don’t push it in too far. Now, you’ll turn the thermometer on. Once it has an accurate reading, it will beep to let you know that it’s done.

For a forehead thermometer, move any hair out of the way, along with any sweat or cosmetics, since all of these can affect the reading. You also shouldn’t use these thermometers outside. Place the thermometer against the forehead and hold down the button until it beeps.

Before you use these thermometers, check the instruction booklet that comes with them. The instructions there might deviate a little bit from the ones we’ve outlined here.


Infrared thermometers have many advantages. They take quick, accurate readings with minimal discomfort. They’re easy to use, and they’re typically very affordable. As long as you buy the right type of thermometer for your needs, you’ll find that getting an accurate temperature reading has never been easier.