Love your brand-new sports cars? Enjoy coming home from a long day of work and thinking about warming up your dinner in the microwave for a satisfying meal? Well, in some way, you have thermistors to thank for that.
While they are not the only components that go into modern technology, they are an essential part. There are many uses from batteries, microwaves, and the medical industry. This article will be all about what are the uses of thermistors.
How Was They First Developed?
Before we check out how thermistors help us build the future in all the cool ways, let’s take a look at the history and see how they were first developed. This will give you more appreciation for these little guys.
We were actually able to show variations of resistors with heat or temperature back in the nineteenth century. Thermistors are generally known to indicate the use of semiconductors. These will give you a larger resistance variation for any given change in temperature.
There are mostly two types of materials used to make thermistors in the modern age. However, the first discoveries were actually metallic compounds. The negative temperature coefficient was observed in 1833 by Michael Faraday. He did this by studying the resistance variations with the heat/temperature of silver sulfide.
Metallic oxides then became commercially available in the 1940s, and then it was also used to make thermistors. And most of them are made from it nowadays too.
There are two types of thermistors, the semiconductor and metallic oxide varieties. They generally cover different temperature ranges. This stops them from competing with each other.
There are many uses of thermistors. In fact, we can bet that just by taking a walk around your house, you will pass something that has a thermistor in it. So, let’s take a bit more of an in-depth look at the uses of thermistors.
The basic thing to know here is they are used as temperature sensors. You can find them in all kinds of everyday household appliances as well as in commercial instruments.
The automotive industry is one of the key users of thermistors. Name a type of vehicle, and it will do not use one. That means cars, buses, trucks, and pickup trucks all use thermistors.
The primary use for them in automobiles is for checking the temperature of coolants and oil. They are connected to the dashboard indicators and are there to inform the driver of the condition of the car – mainly the temperature.
Another important thing is they do not regulate or control the temperature. Ever gotten a warning sign that your car is too hot? Yeah, you have thermistors to thank for that.
Thermistors are used in microwaves to maintain and also determine the temperatures inside. Imagine not being able to know what temperature your microwave oven is. That would essentially make it useless.
There are more dangerous consequences as well. If it did not have a thermistor, the microwave can overheat and be a potential fire hazard. And no one wants that.
Another very common application of thermistors is in digital thermometers. Essentially, thermistors are what make these devices able to tell what someone’s temperature is.
They help give you an accurate reading. Again, they only gather the information for you. It does not maintain it.
Surge protectors use thermistors in a very crucial way. Without it, the energy surge can not be controlled. And this will be bad news for whatever is connected to it.
Excess energy can be pushed through it to the devices and lead to the devices shorting out, causing them to fail.
Thermistors in batteries will stop it from charging if things are getting too hot—that way, the battery is protected. Heat is the worst enemy of all batteries.
Other Applications Where Thermistors Are Used
We have seen some examples and products where thermistors are used. But we figured giving you some other ways they can be used. But instead of products, these will be use cases. Here is a simple list of thermistor applications.
- Temperature control
- Measurement of temperatures
- Temperature compensation
- Measuring high-frequency of power
- Liquid pressure measurement
- Measuring thermal conductivity
Commercial Uses of Thermistors
Commercial uses of thermistors are, frankly, quite a lot. They are used in all kinds of different industries and for all kinds of different things.
The medical industry is one of those which make extensive uses of thermistors in lots of different ways.
Measuring Patient Temperature
Measuring a patient’s temperature can be done by packaging the thermistor in a variety of probes. These can be skin probes or rectal, catheter, and esophageal as well.
Measuring Blood Flow
Matched thermistors can be attached to a catheter. They are generally attached to the tip and then moved to different heart locations to measure the blood flow. They can be flushed with cold saline or heated with a coil.
Blood flow will heat up the saline, which reaches the second sensor, and the first one will get cooled more than the second one. Because the distance between the two sensors is known (and the volume and temperature of the saline are controlled), you can very accurately calculate the output to measure blood flow.
Manufacturing facilities use thermistors as a circuit breaker. If the temperature is getting dangerously high, the circuit will be cut. This is possible since the thermistor can detect temperature changes. Cutting the circuit also protects from fire hazards and damage.
Food and Beverage Industry
Almost everyone knows that food and beverages need to be kept at certain temperatures. Otherwise, there is a chance of them going bad. That is why you will see them being used for monitoring temperatures reliably in different environments.
This helps the food stay at the right temperature, which obviously ensures that they don’t go bad. Pretty important stuff, we would say.
Frequently Asked Questions
1. What are the types of thermistors?
There are two types of thermistors. NTC and PTC. NTC stands for Negative Temperature Coefficient, and PTC stands for Positive Temperature Coefficient.
2. What is the difference between NTC and PTC transistors?
The main difference between the two is how they behave to an increase in temperature. With the Negative Temperature Coefficient variant of thermistors, the resistance will decrease as the temperature rises.
For Positive Temperature Coefficient (PTC) thermistors, as the temperature rises, the resistance will also rise.
3. Which is the most common type of thermistors?
NTC thermistors are very common. They are used in various applications. That isn’t to say that PTC thermistors are not used, though.
Thermistors do a lot. Without them, a lot of our modern technology would be very unsafe to use and be a potential fire hazard. And the medical field, manufacturing facilities, and many other industries have benefited from them as well.
Now that you know what are the uses of thermistors, you can appreciate these little guys a lot more. The next time you get in your car or warm up a snack in your microwave, you can think to yourself, there is a thermistor in there somewhere.
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