termistorien

Termistorien refers to the science and technology of thermistors, temperature-sensitive resistors used for sensing, compensation and control in electronic systems. Thermistors are semiconducting devices whose electrical resistance changes with temperature, providing high sensitivity in a compact, inexpensive form factor.

There are two main families: NTC (negative temperature coefficient) thermistors, whose resistance falls as temperature rises, and PTC (positive temperature coefficient) thermistors, whose resistance increases with temperature. NTC devices are widely used for temperature sensing and circuit protection; PTC devices are used for overcurrent protection and self-regulating heating.

Most thermistors are made from metal oxide ceramics for NTC or doped perovskites and titanates for PTC. They come as beads, discs, chips or rods with protective coatings and leads. The response is nonlinear, described by a parameter known as the B value that relates resistance to temperature.

Common applications include temperature measurement in consumer electronics, automotive sensors, HVAC, medical devices, and degaussing and inrush-current limiting. They provide fast response and low cost but have limitations such as drift with age and nonlinearity requiring calibration.

In practice, thermistor-based circuits are designed as part of voltage dividers or control loops, often with analog-to-digital converters and microcontrollers. They are typically compared with RTDs and thermocouples, chosen for range, accuracy, and sensitivity. Termistorien evolved during the mid-20th century and remains a standard part of electronic design.