Electronic sound control circuit (applause)
This electronic sound control circuit works like a sound activated relay and can activate or deactivate a device connected to it, by two consecutive claps.
Power failure alarm using transformer and relay
This power failure alarm circuit is very simple and is very useful when used with electric ovens, a refrigeration systems or to prevent a thief from cutting off the electrical power because it immediately warns of the problem. It also serves you when the fuses have blown.