The circuit in Figure 1 uses only five I/O lines to drive a dot- or bar-graph display of 20 LEDs. Although this version of the design uses a small and inexpensive one-time-programmable microprocessor, ...

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 ...