Found in the July 1980 Radio Electronics magazine, this circuit uses an integrated circuit from the time and a power Darlington. The Darlington must be equipped with a heat sink.
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...