Found in Popular Electronics from the 90s, this circuit turns off an appliance at the end of the programmed time. The 12 V relay must have contacts according to the controlled current.
This circuit can be found elsewhere on this site as part of alarms or sirens. The circuit given is...
This 3-digit code switch was obtained from an old American documentation. The capacitor is 470 uF...
Found in a 1967 Electronic Design, this circuit changes the phase of a signal in 8 different ways, given...