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.
I found this circuit in a Lujy 1962 English magazine. The circuit is still viable by simply using a...
Instead of the lamps, LEDs can be used in series with 470 ohm resistors. The circuit is from an...
Suggested by a Popular Electronics, this small amplifier that has a detector to follow RF...