10 LED VU Meter Project by LM3915 and LM324

10 LED VU Meter Schematic

Description

VU (Volume Unit) meters are often included in analog audio equipments to display a signal level in Visual Units. We are building a mono input VU meter in this project. You can build one pair to use them in stereo mode.

Input sensitivity is about 1 Volt rms, up to +6dB. You can adjust the input amplitude by using the multiturn 50k linear potentiometer (POT1). Circuit needs symmetric ±12V power supply because of the LM324 opamp. We used metal film resistors (1% tolerance) so accuracy is sufficiently high. Visual duration can be adjusted by using linear 10k potentiometer (POT2). LEDs should be 5mm x 5mm in size for best fit. But we used standard LEDs and this caused a little shift as you can see from the image. Dot/Bar switch determines the operation mode of LM3915.

The PCB file is provided in pdf format. You can apply it to the board by using the ironing method.

Click here to download schematic, layout and PCB files.

Click here to watch the project video.

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Comments (16)

humprey gikungu

How can i get access to the actual circuit diagram

s.h

you can see the download link above

"Click here to download schematic, layout and PCB files."

Jass

what are the components please...?

Hi

When you download the schematic, you can see the components on it.

alp

thank you my frend

Diogo

have a problem using one or lm324n a lm324 opamp?

Jun

how is it connected? what is the input?

mathew

so can u hook it up to speakers? if so wat wattage cuz i dont understand the whole volts to watts thing. or can u hook it up to the rca pluggs on a car amp?