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 detector uses an unusual sensor today. The circuit is from an 80s documentation. Its...
This circuit was found in the December 1976 issue of Radio Electronics magazine. The circuit...
For inductive loads we have the configuration shown in the figure. Note that the opto-coupler...