This circuit with different colored indicator LEDs has an expanded scale. We found it in the March 1992 Radio Electronics magazine. For an adjustable range of 0 to 10.5 V.
For a maximum current of 50 mA the capacitor must be from 470 nF to 250 V if the grid is 110 V and...
We found this high gain circuit with the LM381 preamplifier in a Radio Electronics from February 1990....
January 2017 - The new Schottky SDM02M30LP3 from Diodes Incoporated for 10 mA currents and 30 V...