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.
This circuit was found in a 1965 Electronic Design. Transistor Q2 must be load dependent. The circuit...
This 8-channel converter was found in a 1970s American documentation. The integrated circuits used are...
This rectangular signal generator was found in an Electronics World of 1966. The transistors are...