Found in an Electronic Design from the 90s, this circuit measures the phase difference between two signals using an electronic multimeter. The circuit makes use of components of the time.
This circuit was discovered in an English publication in 1979. The circuit can still be assembled with...
This circuit whose transistors depend on the lamp current was found in Radio Electronics magazine from...
This two-transistor circuit was found in the January 1994 issue of Electronics Now magazine....