A thermistor is a sense resistor. Most thermistors have a negative temperature coefficient of resistance i.e. the resistance of such thermistors decreases when their temperature is increased. Thermistors with positive temperature coefficients are also available.
Thermistors are made by heating under a high-pressure semiconductor ceramic made from mixtures of metallic oxides of manganese, nickel, cobalt, copper, iron, etc. These are pressed into desired shapes and then baked at high temperatures. They may be in the form of beads, rods or washers.
Thermistors with a high negative temperature coefficient are very accurate for measuring low temperatures, especially near 10K. The higher resistance at low temperatures enables more accurate measurement possible.
Thermistors have wide applications as temperature sensors i.e. they convert changes of temperature into an electrical voltage which is duly processed.
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