This circuit detects when there was a power cut, triggering the indicator circuit around it. The circuit is powered by the voltage of a source connected to the grid.
This squelch circuit used in transmitters was found in a magazine for radio amateurs 73 in the...
This audio amplifier with differential input steps is designed to operate with asymmetric sources...
The figure shows how to control the blinking of a 5 V blinking LED with an LDR. The LED only...