This battery-powered micropower supply was shown in Radio Electronics magazine in 1991. The maximum current is 170 mA. and the integrated circuit is the MAX655 from Maxim.
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...