LM3914Ten-step linear LED display driver

LM3914 converts an analog input into ten evenly spaced display levels. A precision resistor ladder and ten comparators drive regulated LED current sinks, so the LEDs normally do not need individual series resistors. The display can show a single moving dot or a growing bar. The reference network sets the full-scale voltage and influences LED current. This example uses a 5 V supply, a nominal 0–1.25 V signal range and about 6 mA per indicator. The reference is not an exact 1.250 V calibration standard: actual thresholds and current follow the device and resistor tolerances. Package choices matter here: the through-hole LM3914N-1 has 18 pins, while the legacy LM3914VX/NOPB SMD part uses a 20-pin PLCC with two unused contacts and different numbering. The manufacturer lists that PLCC orderable as obsolete. All four views follow the selected package; do not wire it using the DIP pin numbers.