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 small experimental transmitter of the figure can be used as a protable microphone or in...
This power supply is not protected from shorts in the output. Output voltage is given by the...
This circuit samples the current in a load and in case of excessive value it activates a...