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 learned the basics and done more research before continuing but I got really eager to start my first project and just went on with it.
After soldering everything, I wired some LEDS to the circuit and powered it up with a 9V (9.9V) dc adapter . All of them lit up and there was no change despite me shouting into the electret mic. I checked the circuit with my multimeter and found that the 3rd pin of NE5532 had an input of 8.6V and the 4th pin of the LM3915 had an input of 5.7V. I'm not sure but according to what I´ve learned about voltage dividers, when R1 =R2 the voltage should be half of my VCC (9.9V).
Anyways, this was probably just one of the many problems my circuit had.
I appreciate any help you can provide!
Thanks!