This squelch circuit is placed at the input of the single receiver audio amplifier stage. Its purpose is to silence background noise. The circuit is from an 80's documentation.
This automatic battery charger was found in a Popular Electronics from the 90s. The circuit uses a...
The slope of an object causes the sensor, a mercury switch to be triggered. The circuit activates...
The assembly of this circuit was described in an article in the magazine Radio Electronics of June...