VU meter, LM3915 Help.

L

LOL_PWND

New Member

• Jun 29, 2010

• #1

Hello!
I'm using this schematic
https://www.instructables.com/files/orig/FX5/67GS/FLROK12R/FX567GSFLROK12R.gif

But instead of using a LM3916, I'm using an LM3915.

This seems to work pretty well, except the first 4 LED's and the last LED don't really light up that bright.

The rest of them do though.

Any recommendations on how to change this schematic to be more accommodate the LM3915?

Thank you.

 

L

LOL_PWND

New Member

• Jun 29, 2010

• #2

Anyone? ):

 

birdman0_o

Active Member

• Jun 29, 2010

• #3

You didn't really provide much information, the last 4 could be because of signal strength. The first 4 would be an issue, your saying the middle 2 work alright?

 

audioguru

Well-Known Member

Most Helpful Member

• Jun 29, 2010

• #4

Instructables are designed by people who know nothing about electronics.

Look at the datasheet for the LM3915. It shows a resistor between pin 7 and pin 8 that is missing in this circuit. The value of the resistor from pin 8 to ground is very high so the LEDs brightness will be low. Also missing is an important supply bypass capacitor. Also missing is a peak detector circuit that is recommended and a few are shown in the datasheet.

 

L

LOL_PWND

New Member

• Jun 29, 2010

• #5

Are you sure o -o

Do you think I should use like 10k instead of 10k from 8 to ground?

 

Last edited: Jun 29, 2010

L

LOL_PWND

New Member

• Jun 29, 2010

• #6

So you think I should stick that 2.2 Capacitor between VCC, Pin 3 and GND?

 

audioguru

Well-Known Member

Most Helpful Member

• Jun 30, 2010

• #7

I corrected the errors. Make it like this:

 

Attachments

• VU meter2.PNG

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