This circuit for audio signals was found in the March 1990 Radio Electronics magazine. The circuit uses a unusual optocoupler that can be replaced with an equivalent one.
This circuit was found in a 1960s General Electric unijunction transistor manual. The circuit can...
In the figure we have the configuration of a variable voltage regulator with two transistors and a...
This circuit was found in Raytheon's 1967 documentation. The circuit uses an operating of the era,...