We found this active crossover in a Radio Electronics magazine from June 1961. Note the different adjustment ranges. The signal must be applied to the amplifier input.
We found this circuit in Popular Electronics from 1992. The circuit uses general purpose...
This approach alarm circuit was found in the September 1970 Radio Electronics issue. The 1 mH coil...
This circuit can function as both a light alarm and a shadow alarm. The components are common. The...