This voice scrambler and descrambler circuit was found in a Radio Electronics from July 1963. Transformers are common types at the time with impedances according to telephones and line.
In a modern version this circuit can use an LED in series with a resistor in place of the lamp. The...
This bistable circuit with SCR for direct current was found in the Radio Electronics magazine of...
The configuration shown in the figure uses two NPN transistors activating the load when the input...