This bistable circuit that drives a relay with a pushbutton was found in the March 1pp6 issue of Electronics Now magazine. A common bipolar with a 1k resistor at the base can be used in place of the FET.
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...