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 VCO or Voltage Controlled Oscillator uses common components. TR1 can be a BF245 and TR2 a...
The transformer for this project found in a 1986 documentation is an output type, found on old...
We found this circuit in a 1978 documentation. The SCR conducts when the regulator's output...