A SRD-05VDC-SL-C 5V relay is a programmable electrical switch, which can be controlled by Arduino or other micro-controllers. It can be programmed to control on/off the devices when a certain event occurs. The relay acts as a bridge between Arduino board and high voltage application. The inside of the relay is connected to an 120-240V electrical switch. When the relay receives a signal, the switch will open or closed. In this exercise, control the fan when the temperature is high by using the normally closed mode of the relay.
Eric-K95/RelayModule-CoolingFan
By using the relay module, the magnetic-relay will control 120V or 240V to turn on/off the cooling fan when it reaches certain temperature.
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