This circuit was found in a 1967 General Electric manual. It shows a SCR control with unijunction and zener diode. The triac depends on the controlled load.
This simple light meter or photometer circuit uses an analog indicator of 0-1 mA. Power is...
Found in a 90's EDN, this circuit provides a current of a few tens of mA. The circuit can generate 15...
The author of this project found in a 1980 documentation gives the radio in two versions: the...