The sensor of this circuit found in Popular Electronics can be formed by a piece of fabric between two bare wire screens. When wet, the fabric will pass the current between the screens, triggering the alarm.
The PA222 integrated circuit used in this project from an American 1967 documentation is not...
This digital CMOS circuit generates sinusoidal signals from a 10 kHz rectangular signal. The...
Found in American documentation from the 90s, this circuit makes use of common components. The load must...