This power supply protection circuit was found in the December 1978 Radio Electronics magazine. The SCR is triggered by shortening the power supply and quickly blowing the protection fuse.
We found this circuit in a 1977 publication for radio amateurs. It serves to test general purpose...
This circuit is from a 1998 Poptronics. The circuit triggers a buzzer after a certain time, waking...
This circuit for electronic voltmeter was found in a publication by Gernsback from 1960. The...