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 operational amplifier circuit with variable gain was obtained in an 80's Electronic...
This audio mixer or mixer was found in a translation of an American publication from the 1980s. The...
September 2017 - Mouser Electronics already has the AP431S adjustable regulator from Diodes...