This circuit uses two quad op-amps to form an eight LED audio level meter. The op-amp used in this particular circuit is the LM324. It is a popular IC and should be available from many parts stores.
The 1K resistors in the circuit are essential so that the LED’s turn on at different audio levels. There is no reason why you can’t change these resistors, although anything above 5K may cause some of the LED’s to never switch on. This circuit is easily expandable with more op-amps, and is not limited to use with the LM324. Pretty much any op-amp will work as long as you look up the pinouts and make sure everything is properly connected.
Read More Source: Circuit : Matthew Hewson
http://www.mitedu.freeserve.co.uk/Circuits/Audio/vumeter.htm
Thank you.
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This entry was posted on Thursday, April 10th, 2008 at 11:00 am and is filed under Audio - Alarm, LED Flasher, meter.
