The LM3914 LED bar graph driver was an amazing chip back in the day. Along with the LM3915, its logarithmic cousin, these chips gave a modern look to projects, allowing dancing LEDs to stand in for a ...
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, ...