termistore

A termistore is a type of resistor whose resistance changes significantly with temperature. The name "termistore" is a portmanteau of "thermal" and "resistor." They are widely used as temperature sensors, self-regulating devices, and in inrush current limiting.

There are two main types of termistores: NTC (Negative Temperature Coefficient) and PTC (Positive Temperature Coefficient). In an NTC termistore, resistance decreases as temperature increases. This behavior is due to the semiconductor material used, where increased thermal energy frees more charge carriers, thus lowering resistance. In contrast, a PTC termistore exhibits an increase in resistance as temperature rises. This is often achieved using materials like polycrystalline ceramics or certain polymers.

Termistores are manufactured from semiconductor materials, typically metal oxides mixed with other elements. Their small size, low cost, and high sensitivity make them suitable for a variety of applications. They can be found in digital thermometers, automotive engine control units, battery chargers, and home appliances like ovens and refrigerators. The specific resistance-temperature characteristic of a termistore is usually provided by the manufacturer in a data table or curve. This allows for accurate temperature measurement or control when incorporated into a circuit.