A thermistor is a type of resistor whose electrical resistance changes significantly with temperature variations. The word "thermistor" is a combination of "thermal" and "resistor." These devices are designed to be sensitive to changes in temperature and are commonly used in temperature sensing and control applications.
The resistance of a thermistor typically decreases as the temperature increases (negative temperature coefficient or NTC thermistors) or increases as the temperature rises (positive temperature coefficient or PTC thermistors). NTC thermistors are more common and widely used.
Thermistors are made from various semiconductor materials, such as oxides of metals like nickel, manganese, cobalt, or iron. The choice of material affects the thermistor's characteristics, including the temperature range over which it operates and its sensitivity.
Due to their temperature-dependent resistance, thermistors can be used in a variety of applications, such as:
Temperature sensors: Thermistors are used in thermostats, weather stations, and other devices to monitor and control temperature.
Temperature compensation: They can be employed to compensate for temperature variations in electronic circuits, ensuring accurate performance over a range of temperatures.
Temperature control: In some heating or cooling systems, thermistors are used to regulate the temperature by turning on or off the heating/cooling elements as needed.
Overcurrent protection: Thermistors can be used as self-resetting fuses to protect circuits from excessive current and prevent damage.
Medical devices: They are used in various medical applications, such as temperature monitoring in patient care.
Thermistors are valued for their reliability, low cost, and ease of integration into electronic circuits, making them a popular choice for temperature sensing and control tasks in a wide range of industries and applications.