This circuit uses an optical coupler called Raystor created by Raytheon in the 1960s. The circuit uses components from the era that can be changed. The current is low.
This timer, using the ZN1034E, is from a May 1987 Radio Electronics magazine. The circuit can...
This circuit was obtained from a Radio Electronics from October 1963. The 4 transistors must be...
This circuit monitors the current in the loads. The NPN and PNP transistors admit the BC547 and...