Op-Amp Circuit: Thermostat Fan
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This is an op-amp circuit that turns on a fan when the temperature goes above a certain threshold. The threshold can be adjusted with a potentiometer.
Op-Amp Circuit: Thermostat Fan Schematic
R2 and the thermistor creates a voltage divider that will output a voltage based on the temperature. The opamp compares this voltage with the voltage from the potentiometer. If the voltage from the potentiometer is higher, the output is low. If the voltage from the thermistor is higher, then output becomes high.
When the output of the opamp is high, the transistor turns on, which turns on the fan.
Op-Amp Circuit: Thermostat Fan Parts List
How to Build the Op-Amp Circuit: Thermostat Fan
This project can be powered by a 9V battery. To test the circuit, you can connect it on a breadboard like shown below:
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