Radio with amplifier (CB20486E)

We found this circuit in a publication of 1991. The audio amplifier is an operational that admits equivalent.

Digitally Controlled Filter (CB14368E)
We found this circuit in the Linear Applications Handbook by National Semiconductor. The circuit is...
Radiation monitor (CB5923E)
This wide-range radiation monitor was found in a 1980s documentation. The circuit uses a diode as a...
Guitar Preamplifier (CB24305E)
This circuit is from an article that appeared in the June 1974 issue of Radio Electronics...