This midrange filter for sound systems was found in the May 1988 issue of Radio Electronics magazine. The circuit is based on a dual amplifier that must be powered by a symmetrical source.
This old slide projector control circuit was found in an 80s Hands On. The circuit uses modern...
In the figure we have a circuit that uses unusual components, being indicated for low frequency...
The sensor of this circuit found in Popular Electronics can be formed by a piece of fabric between two...