Resistors and Thermistors

Resistors are special conductive metals and alloys, such as manganin, each having an accurate and well-known electrical resistivity combined with an extremely low temperature coefficient, and for that reason they are currently used in high-precision electric and electronic instruments and devices like calibrated resistances, shunts, and rheostats. Two major classes must be distinguished depending on their end use  

Electrical resistivity is an intrinsic property of a resistor material that allows for the calculation of the electrical resistance, R, expressed in Q, of a homogeneous conductor with a regular cross-sectional area. A, expressed in square meters, and a length, L in meters. R is given by the following equation, where the proportional quantity, p, is the electrical resistivity of the material, expressed in Q.m  

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The essential part of the thermal chemical sensor is the device that allows fast, sensitive, and precise detection of the temperature a thermometer. There are many thermometers available here we mention only three types, in the descending order of their sensitivity. They are thermocouples, platinum resistors, and thermistors. 

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