Found in old American documentation, this circuit is intended for the control of heating elements. The SCR must have current according to the controlled load. Transistors are from the time.
This circuit is from 2001 documentation, serving to multiplex stereo signals for FM transmitters. The...
This circuit reverses the signal if both positive and negative. We found it in an American...
Found in a publication by Gernsback from 1960, this circuit makes use of germanium transistors of the time....