This circuit, with printed circuit board, is from an article in Radio Electronics magazine from May 1971. The circuit uses the C106 which was already a common component at the time.
This circuit is from a 1998 Electronics Now and can be easily assembled since it uses a common...
We find this circuit in an American 80's documentation. No further information about the...
With this circuit, an external circuit can be controlled by turning it on or off and reversing it (if...