Circuit Switch Sensor Based
The
circuit has been designed to produce a window switch with the use of a thermistor for the main purpose of sensing temperatures.
The circuit mainly serves as a basic resistance-sensing window switch. The function of the resistor is being taken in the form the Negative Temperature Coefficient (NTC) thermistor which is an electronic component and temperature sensitive passive semiconductor that is exhibiting a large change in electrical resistance in accordance with a change in its body temperature. The term thermistor originates from the words “thermal resistor”.
When subjected to an increase in body temperature, the NTC thermistor decreases in resistance. It can perform several unique functions that is impossible to be achieved with standard electronic components because of its extreme sensitivity to minute temperature changes.
The thermistor TH1 in the
circuit should have a resistance in the range of 500 Ohms to 9K Ohms although it works over a relatively small temperature range compared to other temperature sensors and it can provide very precise and accurate sensing.
The use of 10K Ohms potentiometer RV1 is to set half of the supply voltage on the junction of TH1 & sRV1 during the presence of average temperature. The voltage output of the circuit ranges from 0 V to 12 V.