Radio with amplifier (CB20486E)

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

Peak to Peak AC to DC Converter (CB6103E)
This precision circuit was suggested by General Electric in 1980s documentation. The circuit can be...
Digital Control Oscillator (CB1495E )
The resistors R determine the frequencies of the oscillator together with C. The circuit is from a...
Automatic Recorder (CB4889E)
This circuit is intended for recording conversations by amateur radio, being activated by the...