Re: Supplies

> Does anybody have some neons (working units are 
> preferred) that they would like to part with.  I'm not sure what current 
> shipping rates  are, but they are so heavy that it may be wise to buy 
> them locally for 25 to 30 dollars rather than have them shipped.

You would probably be better off just buying them locally since the 
shipping costs alone will probably run $15 to $20.  As an alternative to 
neon sign transformers, you might also try calling your local HVAC 
service companies since you can also use oil burner transformers 
hooked in parallel to drive small Tesla coils.  Happy hunting!

> I think I'll start working on a Van 
> DeGraaf Generator.  Can a neon be used for the power supply 
> directly?  Any suggestions for a belt?  I have seen them in edmund 
> scientific as replacements for there $300 unit.

A van de Graaff generator does not necessarily use a high voltage 
supply.  In it's simplest form, the belt merely transfers the charge 
seperated by friction up to the top terminal.  You can use a high voltage 
DC supply to pre-charge the belt and make the generator more efficient, 
but that's not necessary to make it work.  So, to finally answer your 
question, you would have to rectify the output from a neon sign xformer 
to get the required DC output, but unless you were building a real 
barn-burner of a van de Graaff, it would be gross overkill since you 
would only be using a very small fraction of the xformer output.  A high 
voltage flyback transformer and a voltage multiplier circuit would 
probably be a much better candidate for this application.

I have a book on science fair projects at home that I think has more 
information on building a van de Graaff generator, so when I go home 
tonight, I will dig it up and post any other information I can find (i.e. - 
belt construction, etc...).

Steven Roys (sroys-at-radiology.ab.umd.edu)