This circuit multiplies the input voltage by 3 and can work with up to 12 V input. The current is a few mA. We found it in the Radio Electronics magazine of December 1992.
This alarm circuit was found in a 1990 documentation. However, since it uses only discrete...
This circuit protects galvanometers that are excited by low impedance amplifiers. The circuit is...
This circuit is from a Radio Electronics from August 1952. Types of the time are used, the first...