Radio with amplifier (CB20486E)

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

Dip meter with tunnel diode (CB23732E)
This circuit was found in Radio Electronics magazine from April 1961. The device has a slot for...
FET Follower (CB6132E)
This 1967 Electronics World circuit is suitable for frequencies up to 1 MHz. The setting applies...
Electronic fuse (CB8352E)
Found in a 1968 Motorola manual, this DC circuit uses components from the era. The circuit fires in...