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 is a well-known RC oscillator configuration using a 741 operational amplifier. The circuit is from...
This circuit is from an old 1967 publication. The circuit uses a programmable unijunction...
The circuit found in a 1983 publication is shown in the figure. Taking advantage of the...