Battery Monitor with LM3914
This circuit uses the LM3914 integrated circuit to display battery voltage levels on a series of LEDs in either bar or dot mode. It provides a visual indication of battery charge status, making it ideal for monitoring 12V or other low-voltage batteries.
Circuit Operation
- The LM3914 senses the battery voltage and lights up 10 LEDs proportionally, forming a bar or dot display depending on the mode selected.
- Each LED corresponds to a voltage step, providing an intuitive visual representation of the battery charge.
- The reference voltage and LED mode can be adjusted to match different battery types and voltage ranges.
Key Features
- Displays battery voltage level with 10 LEDs
- Selectable bar or dot display mode
- Simple, compact, and reliable design
- Adjustable reference voltage to match battery type
- Works for 12V batteries or other low-voltage applications
Construction Notes
- Use low-tolerance resistors for the voltage reference to ensure accurate LED display steps.
- Connect LEDs with correct polarity; the IC sinks current, so LEDs connect from +V to output pins.
- Keep battery input wiring short and avoid interference for accurate readings.
- Optionally, add a series resistor for each LED to adjust brightness or protect the LEDs.
| Ref. | Components |
|---|---|
| U1 | LM3914 Bar Dot Generator IC |
| R1 | 100KΩ potentiometer |
| R2 | 1KΩ resistor |
| LED1-10 | light emitting diodes (LEDs) |