This circuit was obtained in an Electronic Design from the 80's. It has the adjustment of the gain through a simple potentiometer. The power supply must be symmetrical.
Found in a 1964 Electrronic Design, this circuit is intended to control analog video signals. The...
We find this microphone voice effect in 1992 documentation. The vibration of the relay contacts...
This circuit for some amps was found in a 90s Radio Electronics. The voltage can be between 6 and 25 V...