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 circuit for frequencies of 20 to 2 kHz was obtained in English documentation from 1966. The...
The oscillator of this circuit operates around 8 MHz, but the output will be at a frequency three times...
This circuit with transistors of the time was found in the magazine Radio Electroinics of June of...