thermistor


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Related to thermistor: thermocouple

thermistor

a semiconductor device having a resistance that decreases rapidly with an increase in temperature. It is used for temperature measurement, to compensate for temperature variations in a circuit, etc.

Thermistor

An electrical resistor with a relatively large negative temperature coefficient of resistance. Thermistors are useful for measuring temperature and gas flow or wind velocity. Often they are employed as bolometer elements to measure radio-frequency, microwave, and optical power. They also are used as electrical circuit components for temperature compensation, voltage regulation, circuit protection, time delay, and volume control. Thermistors are semiconducting ceramics composed of mixtures of several metal oxides. Metal electrodes or wires are attached to the ceramic material so that the thermistor resistance can be measured conveniently. See Bolometer, Electrical resistivity

At room temperature the resistance of a thermistor may typically change by several percent for a variation of 1° of temperature, but the resistance does not change linearly with temperature. The temperature coefficient of resistance of a thermistor is approximately equal to a constant divided by the square of the temperature in kelvins. The constant is equal to several thousand kelvins and is specified for a given thermistor and the temperature range of intended use.

The resistance and heat capacity of a thermistor depend upon the material composition, the physical dimensions, and the environment provided by the thermistor enclosure. Thermistors range in form from small beads and flakes less than 10-3 in. (25 micrometers) thick to disks, rods, and washers with inch dimensions. The small beads are often coated with glass to prevent changes in composition or encased in glass probes or cartridges to prevent damage. Beads are available with room-temperature resistances ranging from less than 100 &OHgr; to tens of megohms, with heat capacities as low as tens of microwatts per degree celsius, and with time constants of less than a second. Large disks and washers have heat capacities as high as a few watts per degree Celsius and time constants of minutes. See Temperature measurement, Time constant

thermistor

[thər′mis·tər]
(electronics)
A resistive circuit component, having a high negative temperature coefficient of resistance, so that its resistance decreases as the temperature increases; it is a stable, compact, and rugged two-terminal ceramiclike semiconductor bead, rod, or disk. Derived from thermal resistor.
References in periodicals archive ?
Thermistors are small pieces of semiconducting material that exhibit large changes in resistance for a small temperature variation.
Temperature of transducer's thermistors was measured only after 60 minutes after the temperature of the Peltier element reached the target value in order to stabilize the flow of heat.
Temperature sensing, controlling, and compensating with thermistors all serve to protect sensitive components.
The measuring method bases on the measurement of the voltage drop across the thermistor, which is fed with the same reference voltage as the multislope ADC for further signal processing.
Tudor temperature sensors include a full range of high- and low-temperature thermocouples, RTDs, thermistors, temperature transmitters, probe heads, and accessories.
Overall, thermistors are more stable than thermocouples, but their temperature range is not as broad, nor their response time as rapid.
The thermistor powers were approximately 100 [micro] W.
an innovator in electronics, has introduced three new 0603 package Thermistors to adjust to the demands of downsizing in the computer and automotive markets.
T] is the thermistor resistance at the temperature T, and T is the temperature in K, and A0, A1, A2, A3, A4 and A5 are the coefficients.
It is designed to directly read calibrated RF power with 100 ohm and 200 ohm thermistor style RF power sensors from manufacturers including: Agilent, TEGAM, Weinschel, Hughes, General Microwave, EIP and Milltech.
The interior glue and thermistor are specified for high temperature use, and a valve allows the pack to vent.
The modification was made to the thermistor because oF poor ductwork in those shelters.