LED VU Meter by LM339 PCB


Posted on Feb 5, 2014

The circuit below uses two quad voltage comparators (LM339) to illuminate a series of 8 LEDs indicating volume level. Each of the 8 comparators is biased at increasing voltages set by the voltage divider so that the lower right LED comes on first when the input is about 400 millivolts or about 22 milliwatts peak in an 8 ohm system. The divider vol


LED VU Meter by LM339 PCB
Click here to download the full size of the above Circuit.

tages are set so that each LED represents about twice the power level as the one before so the scale extends from 22 milliwatts to about 2. 5 watts when all LEDs are lit. The sensitivity can be decreased with the input control to read higher levels. I have not built or tested this circuit, so please let me know if you have problems getting it working. The power levels should be as follows:




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Bridge Rectifier
    Receiver Frequency-Converter Stage
    Low-Offset Simple Video Buffer Circuit
    PIC Traffic Lights
    A Fluid Sensor
    Adjustable High/Low Frequency Sine wave generator
    Transformerless Voltage Booster Circuit: A DC-DC Step-Up Switching Regulator Using Transistors
    Stereo PC Speaker Powered USB Speaker Schematic Diagram
    eminent
    Car Boot Lamp Warning (ICM7556)
    Lamp flasher circuit
    Crystal Oscillators
    Pressure Measurement from five-channel low-power programmable sensor signal processor AD7714



    Top