We found this circuit in the October 1996 Electronics Now magazine. The circuit uses LDRs as sensors and drives relays. The relays must have voltages according to the power supply.
Found in a PE Hobbyst Handbook, this circuit checks if there is voltage in a power outlet by...
Here is a high-quality intercom for demanding readers. The circuit is from a 1982 documentation. Of course,...
This circuit shows how to use a low current read switch to control high power loads. The circuit...