We found this circuit in the March 1984 issue of Radio Electronics magazine. The module used is a common type at the time. The other integrated circuits are common types.
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...