Radio with amplifier (CB20486E)

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

Code Switch (CB1354E)
This 3-digit code switch was obtained from an old American documentation. The capacitor is 470 uF...
Antenna Amplifier (CB3869E)
This antenna or booster amplifier operates with signals from the midband (MW) range up to the VHF...
Divide-by-3 Counter (CB158E)
The circuit presented here shows how two flip-flops of a 4027 can be connected to perform a...