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Adafruit Panel Volt Meter - 4.5V to 30VDC [ADA575]
Put a voltage meter anywhere with this very handy display. This panel meter simply connects to whatever DC supply you are trying to track, easy to wire up!
Simply connect the red wire to the positive supply, and black to negative ground. The display has a microcontroller that will read the voltage, compare it to a stable reference and display the voltage with 0.1V precision on a 3-digit 0.56" tall 7-segment display. It works from 4.5V up to 30V and is reverse-polarity protected so it will be good for nearly any electronic project! The meter draws 3-4mA to power the microcontroller and display. This particular LED display is a nice vivid green, which we found very readable. To mount to your enclosure, simply cut a 45.5mm × 26.5mm rectangle and snap it in.