Found in a Popular Electronics from the 90s, this circuit activates a recorder for automatic recording of telephone calls. The circuit was used with old cassette recorders of the time.
This audio generator that produces both rectangular and sinusoidal signals was found in a...
This simple timer causes an LED to blink after an interval of the order of 7 minutes which is the...
This charger for small batteries was obtained from the 1982 Radio Experimenter Handbook. The...