PTC Thermistors

PTC – positive temperature coefficient – thermistors are used as resistors in electrical circuits. Positive temperature coefficient means that as the temperature increases, so does the resistance provided by the thermistor. PTC thermistors help to protect other electrical elements within circuits from blowout by limiting the current they’re exposed to, and as such can also lengthen the lifespan of these elements.

What are PTC thermistors used for?

PTC thermistors can be used as inrush current limiters or for overcurrent protection. How they’re used will depend on the specific device and circuit they’re used in. PTC thermistors are commonly used in telecoms and security devices to ensure they can continue working if they suffer electrical surges during storms.

How do PTC thermistors work?

PTC thermistors have low levels of resistance at room temperature. When the flow of electrical current raises the temperature of the PTC thermistor, this causes resistance to increase, thus reducing both the flow of electricity and the temperature.

What are the benefits of using PTC thermistors?

PTC thermistors work in the same way fuses do, but don’t need replacing each time they have limited current, simply returning to its’ low resistance state once the temperature reduces.

What’s the difference between PTC and NTC thermistors?

PTC thermistors increase resistance as temperatures increase, while NTC – negative temperature coefficient – thermistors decrease resistance as temperatures increase. Despite the differences in how they work, they can both be used for similar specific functions such as inrush current limiting.