This latched alarm uses a double relay for this purpose and can control higher power external loads like a siren. The circuit is from 1974 documentation and has a very low consumption.
We found in this American documentation this circuit for activating common cathode displays. In it we...
This interesting shield circuit was obtained from a Poptronics of February 2001. The American...
This RCA commercial radio had its circuit published in Radio Electronics magazine in August 1959....