This simple continuity tester, whose configuration can be found several times on this site, is powered by only 2 batteries providing the indication on an LED.
Found in a 1964 Electronic Design, this circuit is intended to serve as a time base for cardiac...
A modulated (intermittent) siren, using the four gates of the 4001 integrated circuit is shown in the...
Other operational amplifiers can be used in this conventional filter that rejects only one...