The main function of thermistors is to be sensitive to temperature, which shows different resistance values at different temperatures. Thermistors can also be used as electronic circuit components for temperature compensation of instrument circuits and cold junction temperature compensation of thermocouples. Using the self heating characteristic of negative temperature coefficient thermistor, automatic gain control is realized, and the amplitude stabilization circuit of RC oscillator is constructed. When the self heating temperature is much higher than the ambient temperature, its resistance is also related to the ambient heat dissipation conditions. Thermistors are usually used to analyze flow meters, flow meters and thermal conductivity to make special detection elements.