This step of good gain was obtained in an American publication of the 1980s. The circuit can be powered by voltages from 3 to 9 V and the FET can be of almost any type.
This thermal control circuit appeared in Radio Electronics magazine in October 1958. The circuit is...
This small medium wave radio was manufactured in the 1960s in Japan. The circuit is powered by 4...
This circuit is from a 1988 publication. It makes use of an LM3914 LED driver circuit, still...