⇒ Thermistors are a type of resistor that change their resistance with temperature
⇒ Most thermistors are negative temperature coefficient (ntc) components, meaning their resistance decrease with temperature
⇒ Thermistors are widely used in circuits to sense temperature changes, and then to control devices; the change in the resistance of the thermistor affects a current, which can be used to switch devices on or off
⇒ They can be found in thermal cut-off circuits to prevent devices from over-heating (such as a hairdryer), central heating circuits, digital thermometers and engine-management circuits