# CCFL VU meter

Discussion in 'The Projects Forum' started by funguypie2, Nov 22, 2012.

1. ### funguypie2 Thread Starter New Member

Nov 22, 2012
1
0
So i wanted to do a DIY project over the winter break where I make a bookshelf and put a VU meter up the sides of the shelf, at first I thought to use LEDS but thought it would be too hard to put the leds in the shelf. Then I found this schematic for a VU meter with CCFL's and was intrigued. Of course, knowing nothing about circuitry, I took it to my nearest radioshack and asked for some help, but the guy had lots of questions about the schematic.
1. What does the from speaker terminals and J1 mean?
2. is the capacitor a electrolitic or a ceramic disk, and is it 47 uf or 4.7 uf
3. what does the 2m2 mean by R1
4. what is the voltage of the op amp
5. what is the ohm value of R4 R5 and R6
6. what does the TO tube driver power input mean?

http://www.flickr.com/photos/26426397@N00/5332351560/
heres the schematic link

http://www.youtube.com/watch?v=U4gBWAnF24k
and the video where I got the idea from

Thanks for all the help

2. ### Dodgydave AAC Fanatic!

Jun 22, 2012
8,286
1,447
R4,5,6 are 22ohms each, the supply is 12volt, the capacitor is 4.7uF. R1 is2.2meg

3. ### tubeguy Well-Known Member

Nov 3, 2012
1,157
198
J1 of the circuit connects to a speaker output on your stereo. 'To tube DRIVER..." connects to the power inverter supplied in the kit below.

http://www.parts-express.com/pe/showdetl.cfm?partnumber=130-251

Capacitor is electrolytic. Note the + sign.
It's 2M2 or 2.2 MEG (million) ohms. Big M means MEG, small m means milli.

I type too slow
Needs to handle 12VDC.
22 ohms each, in parallel, 22/3 = 7.3 ohms, 8 ohm 1-watt OK also

The circuit needs some 'tweaking' for safe operation with a powerful stereo.

Check back later, Holidays...

Last edited: Nov 22, 2012
4. ### Audioguru Expert

Dec 20, 2007
11,251
1,350
The polarity of the 4.7uF input capacitor C1 is BACKWARDS!