This circuit uses two National Semiconductor LM3914 dot/bar-display-driver ICs to implement a two-digit, 0 to 5V LED voltmeter that mimics a subranging flash ADC. An LED bar graph comprising five LEDs ...

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, ...