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Just started with electronics a few days ago. I decided to build a microphone based VU meter using LM3915 and NE5532 for my first project.
I wired the LM3915 according to the datasheet for a scale between 4.5 V and 7.5V together with some preamp schematic I found on Google.
I really should have...
After searching the internet, I got a lot of clues but no answer. Here is the answer.
The LM3915 bar / dot display driver wants an analog input up to 1.25 volts where the tenth LED comes on.
Arduino analog output is actually PWM at 5 volts, using a 5 volt supply.
This gets a smooth voltage...