This circuit is a four-quadrant multiplier using an LM3900. The circuit was found in the July 1988 Radio Electronics magazine.
This circuit has an interface for a multimeter or electronic voltmeter. We found it in a 90s...
This circuit was found in Radio Electronics from the 90s. Q3 must have a heatsink and R10 fixes...
This voice scrambler is used to obtain effects in the 2.5 to 5 kHz range. The circuit is from...