The RCA integrated circuit used in this control is uncommon today. The circuit is from an Electronics Now from July 1995. The sensor determines the value of the adjustment potentiometer.
In the figure we show a timer, this simple one with only one of the four gates of integrated...
This circuit is a sensor for photodiodes that can be used in optical couplers, encoders and other...
This crystal tester was found on a 90s Ham Radio. Transistors are commonly used. The circuit is for...