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A thermistor is type of resistor whose resistance varies significantly with the temperature. it is constructed of semi conductor material with a resistivity that is especially sensitive to temperature.
Working principle of
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Thermistor:
A thermistor is a type of resistor whose resistance varies significantly with temperature. Thermistors use internal electrodes that sense surrounding heat and measure it through electrical impulses. They also help to control heat to some extent, usually causing the device to which they are attached to heat up much more slowly than it normally would. They are made with semi-conductor materials using temperature-sensitive resistanceThe material used in thermistor is generally a ceramic or polymer. There are two kinds of thermistors: NTC (Negative Thermal Coefficient) and PTC (Positive Thermal Coefficient). With the former, the resistance of the thermistor decreases as the temperature increases, and with the latter, the resistance increases as the temperature rises.
The basic mathematical model used for thermistors is the Steinhart-Hart equation, discovered by oceanographers I.S. Steinhart and S.R. Hart. In its simplest form it is:
1/T = a + b(ln R) +c(ln R)3
where T is the = temperature, a,b , and c are = coefficients that are measured, ln is the natural log, and R is the R= resistance in ohms.Ohms.
Advantages:
1) They are cheap.
2) Stable
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