Found in a 90’s Electronics Now, this circuit has its output connected to an audio amplifier. The transducer is the type that fits on the finger to monitor the transparency and thus the beats.
Found in an American publication of 1968, this circuit makes use of a pilot light of the time. It...
This circuit was found in documentation from the 1980s requiring a variable power supply from 0 to...
This car alarm was found in an American '80s documentation. The circuit automatically activates...