Digital display temperature detection circuit

Digital display temperature detection circuit

Shown is a high-precision digital display temperature detection control circuit
. MC1403 pin ② outputs a reference voltage. The reference value is set by potentiometer RP5 and added to the inverting terminal (one) of IC 4. The thermistor (temperature sensor) PT100 is added to the negative feedback loop of ICI. The
thermistor , so the negative feedback amount of IC1 changes, the gain of ICI changes accordingly, and the output of lC] The comparison
voltage formed by IC3 is applied to the non-inverting input of IC 4 and compared with the output of RP5. The increase in the comparison voltage causes VT to conduct, and the relay operates to control the heater
and other equipment to start running. At the same time, the voltage value representing the temperature is sent to the A/D converter L7107, which converts the analog signal into a digital signal, and displays the temperature value
through a digital display .