With a single LED on the scale, this voltmeter has low consumption. The circuit was found in the March 1992 issue of Radio Electronics magazine.
This is the project found in a 1981 publication, but it is still viable. It is a simple AM...
This commercial earphone receiver was manufactured in the 1960s in Japan. It was powered by a 9 V...
This circuit was found in a European publication from the 1980s. The transistors can be the BC548...