This circuit also appears elsewhere on this site, obtained from other sources. This is an 80's American schematic book. Instead the lamp can be used white high-brightness LEDs.
This receiver for listening on the phone was found in a Japanese magazine in 1967. The circuit uses...
This circuit is activated by the ignition key which, when removed, makes a relay beep if the...
This circuit emits an alert sound (interval beeps) if the car lights are left on and the ignition key...