Basic application circuit of thermistor a

The basic application circuit of the thermistor is shown in the figure .
    Figure (a) shows the most basic temperature measurement circuit. The temperature measurement accuracy of this circuit is not high and can only be used in
situations where accuracy requirements are not high. When RT is a positive temperature coefficient thermistor, when the temperature increases, the output voltage vo increases, and vice versa;
when RT is a negative temperature coefficient thermistor, when the temperature increases, the output voltage vo decreases, and vice versa.
    Figure (b) is a thermistor temperature difference measurement circuit using an operational amplifier, and the temperature measurement accuracy is improved. This
circuit can detect the temperature difference between two points. When the temperature at RTi is lower than the temperature at RT2, that is, RTi <RT2, the potential of
terminal (1) of the operational amplifier is higher than the potential of terminal (+), and the output is low level; In the same way, when the temperature of month L is higher than the temperature
of RT2 , the output is high level.     Figure Il (c) is a temperature measurement circuit using an operational amplifier and a logarithmic diode. The logarithmic diode compensates for the linearity of the thermistor , and RP can adjust the gain of the amplifier, thereby further improving the output characteristics.