As shown for the basic application circuit thermistor. Figure (a) of the basic temperature measurement circuit. The circuit temperature measurement accuracy
is not high, can only be used for less demanding precision applications. RT is a positive temperature coefficient thermistor, the temperature rises, the output voltage vo is increased, decreased and vice versa; RT negative temperature coefficient thermistor, the temperature rises, the output voltage vo is lowered, increased and vice versa. Figure (b) is measured using a thermistor temperature differential operational amplifier circuit, temperature measurement accuracy improved. This circuit can detect a temperature difference between two points, which when RTi RT2 at a temperature lower than that RTi <RT2, operational amplifier (a) end potential is higher than (+) side potential, the output is low; Similarly, the month in which the temperature is higher than L RT2 when the temperature at the output is high. FIG Il (c) is the use of an operational amplifier and logarithmic diode temperature measurement circuit, logarithmic diode thermistor linear compensate, RP adjustable gain of the amplifier, thereby further improving the output characteristics.