The purpose of this circuit is to measure the intensity of audio signals. We found it in the September 1990 issue of Radio Electronics magazine. The circuit works as a S meter.
In the figure we have the simple way to obtain a digital inverter using a general-purpose...
This sensitive receiver with earphone was found in an English documentation from 1963. The...
Found in an Electronic Design from the 90s, this circuit measures the phase difference between two...