Using the CA3140 in the figure we have a comparator that goes low in the window voltage space. The circuit was found in June 1986 Radio Electronics magazine.
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...