Found in a Popular Electronics from the 9s, this circuit has output for RS-232 interfaces and current input. The power supply must be symmetrical.
This circuit for vehicular use is from an 80's American publication. The circuit has a light...
You can change the output voltage of a fixed 3-terminal regulator using a zener diode. The voltage of...
This circuit was found on a Radio Elettronica (Italy) from April 1974. The circuit can still be...