This circuit is a four-quadrant multiplier using an LM3900. The circuit was found in the July 1988 Radio Electronics magazine.
This basic configuration of voltage regulator using operational amplifier and zener was found in a...
This 75 W power supply was found in American documentation from the 1980s. Transistors can be...
This circuit was found in a 1987 magazine. It measures the pulse rate produced by a cardiac...