There are two type of thermistors as NTC ( negative temperature coefficient ) and PTC -
positive temperature coefficient. Thermistors are some kind of sensors. We can call it as
Input transducer as it converts temperature or heat in to resistance.
How NTC Thermistor works ?
When connected a NTC thermistor to a circuit we can say that there is no continuity as it
has very high resistance inside the thermistor. But the resistance will go down with the
for a example if you want to run a small fan when heat goes up you can use NTC
thermistor for that. The fan get supply voltage through the NTC thermistor and it will
automatically get off when the heat decrease.
We hope as a beginner you can get rough idea about what is NTC thermistor is.
How PTC Thermistor works ?
Just remember the PTC thermistors act opposites to the NTC's. When there is no heat
PTC thermistors pass the current without any resistance. Its resistance go high with the
heat.This type of thermistors we use to protect and control the electronic devices. As a
example you can think about a Iron.
The good side of the thermistors are when connecting to circuits we don't have to bother
about polarity or soldering heat. Thermistors are commonly used in power amplifiers,
Irons, Refrigerators, Electric ovens, etc..