LEDs often are used to form a dot/bar graph display.1-4 You also can use an LED dot-graph display as a complement to a digital voltmeter (DVM) with the LM3914 dot/bar display driver and nine LEDs.5 This is useful where the input voltage is unstable, so the voltmeter indications are variable and the result is hard to read and understand.
By adding an associated circuit, the DVM measures and displays the approximate mean value of the input voltage, while the LED dot-graph provides information about the voltage’s stability. This approach is suitable for rapidly testing power supplies.
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