Electronic equipment, such as computers, printers, air conditioners, TVs, etc., use electricity when in use, but still use some electricity when not in use; most electronic devices have power switches, but they still consume some electricity when in use . This can save a lot of fuel. But in most cases, users cannot completely turn off these devices. The construction of a given project takes this into account, and the circuit will generate a sound signal every minute to instruct the device's power switch to remain on.
Circuit diagram and Working Explanation
After the circuit connecting the power supply and the circuit is established, the power supply can be two 3V lithium coin cell batteries. The current circuit consumption is only 650uA, so the battery life is longer. Use a small antenna cable for better performance and place it next to the 220V AC electrical cable. The circuit is very sensitive, and the sensitivity can be modified by connecting a 1M variable resistor. The circuit sequence can be modified by the 1 M variable resistor connected between pin 6 and pin 7 of IC2.
The best feature of this circuit is that it does not need any physical connection with the wires of the device, it only needs to place the antenna near the wires, and the rest of the work is done by it.