Vu Meter LM324
This audio VU meter uses the LM324 operational amplifier to drive a series of LEDs, providing a visual indication of audio signal levels. The circuit can be adapted for multiple LEDs to form a thermometer-style display.
Circuit Operation
The LM324 amplifies and processes the audio input signal, converting its amplitude into a voltage level that drives the LEDs. As the input signal increases, more LEDs light up, creating a moving light bar to indicate the instantaneous audio amplitude.
Key Features
- Displays audio signal amplitude using multiple LEDs
- Thermometer-style LED display for intuitive visualization
- Uses the LM324 quad op-amp IC
- Input signal can be adjusted via a potentiometer for calibration
- Flexible design suitable for desktop or DIY audio projects
Construction Notes
- Use LEDs with similar brightness for uniform display.
- Include current-limiting resistors for each LED as per design calculations.
- Keep audio input wiring short and shielded to minimize noise.
- Use a suitable supply voltage for the LM324, typically 9V to 12V DC.
- Ensure the op-amp is mounted on a PCB with proper decoupling capacitors close to the IC.
