Neon bargraph project help

Thread Starter


Joined Oct 15, 2011
Hi All,

New to the board, done a number of hobbyist things in the past, still a little new on all of this...

I am looking to build this particular project that uses neon bar graphs as indicators for an Audio Spectrum visualizer.

I found this project here, along with schematic:

Also found the same project in

Trying to figure out what types of caps, resistors and potentiometers to use.

I am guessing that all the resistors are 1/4 watt, +/- 5% carbon or metal film, but I may be wrong.
Also not sure about what type and rating the caps should be.. looks like the 100uf's are Aluminum electrolytics rated at 35V and the 4.7 are the same, rated at 50v... not sure about the rest.

Any help on component selection would be greatly appreciated! It looks like a pretty cool little gadget....


Joined Nov 30, 2010
The capacitors can be 16 volts. That way they will survive if you accidentally get 12 volts connected to a place that should be 6 volts. 1uf and up can be aluminum electrolytic. Below that, poly-whatever types. (Polyethylene, polypropolene, polyunpronouncable, etc.) I don't see where 35 or 50 volt capacitors are needed.

The resistor values have 2 digits, so they aren't 1% or 2% quality. That leaves 5% and 10%. Most likely 5%.

Potentiometers that don't say, "A" or, "AT" are linear. Linear pots often have "B" marked on them. If they have the "A" marking, they are audio taper.

It's all low voltage, low power, except for the 120V neon displays. Not a problem.


Joined Nov 30, 2010
I found the photo.
This is mostly correcting myself.

I can see the 35 volt capacitors, but they aren't needed for a 12 volt Vcc. The manufacturers say that buying more than double the supply voltage does not cause any further improvement in lifespan. This board should never see any electrolytic capacitor over 25 volts, just because the higher voltage caps cost more and improve nothing. I also see ceramic capacitors in blue and tantalum caps in yellow. Probably better than poly caps because they are much smaller and you don't need poly quality because you aren't going to listen to the output.

The resistors are definitely 5%.

The pots are all single turn linear trimmers. Minimum wattage.