How does a PTC thermistor react?

A PTC thermistor works a little differently. When temperature increases, the resistance increases, and when temperature decreases, resistance decreases. This type of thermistor is generally used as a fuse.

How do PTC and NTC thermistors operate?

Thermistors are available in two types: those with Negative Temperature Coefficients (NTC thermistors) and those with Positive Temperature Coefficients (PTC thermistors). NTC thermistors’ resistance decreases as their temperature increases, while PTC thermistors’ resistance increases as their temperature increases.

Where is PTC thermistor used?

PTC thermistors for overcurrent protection Ceramic PTC thermistors are used instead of conventional fuses to protect loads such as motors, transformers, etc. or electronic circuits against overcurrent. They not only respond to inadmissibly high currents but also if a preset temperature limit is exceeded.

What happens to the resistance of a PTC thermistor when it is heated?

PTC = Positive Temperature Coefficient thermistors. That is, the resistance increases as the temperature increases. That is, the resistance decreases as the temperature increases.

Why do thermistors decrease resistance?

NTC thermistors, resistance decreases as temperature rises due to an increase in conduction electrons bumped up by thermal agitation from valency band.

How are thermistors used?

Thermistors are used as temperature sensors. They can be found in every day appliances such as fire alarms, ovens and refrigerators. They are also used in digital thermometers and in many automotive applications to measure temperature.

How do you test a PTC thermistor?

Testing a PTC thermistor follows all the same steps as a NTC thermistor. First check, with an ohmmeter, the thermistor without any heat applied. With a PTC thermistor at room temperature or below, the thermistor should measure a very low resistance. Now apply heat, just like before, to the thermistor’s body.

How does a PTC fail?

PTC system failures include failure to enforce a permanent speed limit, failure to enforce a temporary speed, or a failure to be able to determine the correct speed limit due to a database error where the correct speed limit cannot be found.