Found in an American documentation from 1969, this astounding circuitry makes a relay operate on 3 Hz cycles. The relay is of the high voltage type of the time.
This signal injector uses a single integrated circuit as an oscillator, producing rectangular...
We found this circuit in an old American documentation (80's). The circuit generates sine signals...
This is a VU-meter bargraph with up to 7 LEDs according the Power supply voltage. Adjusts are made by...