This circuit for audio signals was found in the March 1990 Radio Electronics magazine. The circuit uses a unusual optocoupler that can be replaced with an equivalent one.
The purpose of this circuit is to improve the reception of signals from the short-wave band. The...
This highly sensitive light sensor was found in a 1970 General Electric documentation. The circuit...
This circuit was found in a Popular Electronics from the 90's. The CMOS integrated circuit used is...