The thermistors are usually made of
-
metals with low temperature coefficient of resistivity
-
metals with high temperature coefficient of resistivity
-
metal oxides with high temperature coefficient of resistivity ‘
-
semiconducting materials having low temperature coefficient of resistivity.
C.
metal oxides with high temperature coefficient of resistivity ‘
These are devices whose resistance varies quite markedly with temperature mean having high-temperature coefficient of resistivity. [Their name are derived from thermal resistors]. Depending on their composition they can have either negative temperature coefficient or positive temperature coefficient or positive temperature coefficient or positive temperature coefficient characteristics. The negative temperature coefficient types consist of a mixture of oxides of iron, nickel and cobalt with small amounts of other substance. The positive temperature coefficient types are based on barium titanate.
