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.
This circuit drives two-color LEDs at a speed that is set in the 100k pot. The circuit can be...
The circuit shown was found in a 1967 RCA manual. Modern equivalent components can be used. The...
Indicated for automotive applications, this circuit was found in the November 1980 issue of Radio...