Found in a 1964 CQ magazine this circuit consists of an automatic telegraphic key, providing the correct duration for points and dashes. The circuit can be made with a current PNP transistor.
This circuit is from old American documentation intended to trigger the flash of a camera flash with...
The UVTRON tube is an ultraviolet radiation sensor. In this circuit from Radio Electronics from...
This tester from a 1960 magazine is only for capacitors with insulation voltages above 200 V (110...