Thermistors

Abstract

Thermistors are transducers constructed of ceramic materials whose electrical conduction properties are temperature sensitive. These devices have been developed to be very sensitive, having excellent long‐term stability, and small size. Thermistors are also relatively inexpensive, presenting a lower cost than either resistance temperature detectors or thermocouples. These characteristics probably situate this device as the most widely used temperature transducer for medical applications nowadays. It makes them ideal for healthcare products that incorporate sensor probes that can be discarded after using and replaced for new ones with the same specification, without recalibration. In this article, thermistor terminology, electrical and thermal properties, linearization, and the basic electronics used in temperature measurements are discussed. Examples of commercial devices dedicated to temperature measurements are also presented. Beyond their utility in temperature measurements, thermistors have found widespread use in a variety of systems for clinical and research applications, such as the measurement of flow, thermal conductivity and diffusivity of biomaterials, and the detection of the presence of liquids. This article includes a brief discussion about these applications, showing the branches of medicine where technology based on thermistor is used, and how this technology can assist each of them.

A review on various temperature-indication methods for Li-ion batteries

“…This behaviour is shown in Fig. 8 (curves a, b and c) [182], in which it can be seen that NTC behaviour is nonlinear, making temperature indication somewhat challenging. For thermistors that have a positive temperature coefficient (PTC) this behaviour is the other way around, i.e.…”

“…The resistance increase of a platinum RTD is shown in Fig. 8 (curve d) [182]. This figure shows that a platinum RTD is less sensitive to temperature changes than NTC thermistors.…”

“…Thermistors have the advantages of being inexpensive, highly sensitive to temperature changes ( Fig. 8), applicable across a considerable temperature range (-55 to ~300 o C), available in different forms, and can be very small [182]. Due to the small size, it is possible to respond quickly to temperature changes.…”