This 1969 Mullar circuit appears elsewhere on this site. The circuit uses germanium diodes and the indicator is microammeter with zero in the center of the scale.
July 2017 - Microchip's new MCP39F511 demonstration and development boards, which consist of...
This circuit, which controls both the temperature and the level of a liquid in a reservoir, was...
This circuit provides a constant current of 1 mA, stabilized by an LED, which can be equivalent to that...