We found this circuit in a 1980s General Electric documentation. It appears from other sources in this section. The circuit makes use of diacs and SCRs of the time.
This proximity relay circuit was found in the July 1990 Radio Electronics magazine. The supply...
This circuit is from an old operational amplifiers manual. However, the setting applies to modern...
Using an operational amplifier, the figure shows how to convert the waveform to low frequency...