Re: neon transformer



On Wed, 14 Nov 2007 07:31:34 +1300, "Roger Dewhurst"
<dewhurst@xxxxxxxxxx> wrote:


"default" <default@xxxxxxxxxxxxx> wrote in message
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On Tue, 13 Nov 2007 13:22:41 +1300, "Roger Dewhurst"
<dewhurst@xxxxxxxxxx> wrote:

Some time ago I saw an advertisement, or thought that I did, for a neon
transformer, a high voltage transformer about half the size of a pencil.
Do
these things exist and where might they be found? Google offers no help.

R

There's a cold cathode fluorescent lamp supply about the size of a
pencil but that is for ~1 watt.

Perhaps that is the thing. Is it a step-up transformer?

Small circuit board with an inverter similar to the things used to
charge photo flash caps on cameras.
http://www.escience.ca/hobby/RENDER/0001/13/3096/11695.html has a
picture - quite large actually about 2-3/8" X 7/8" X 5/8"

http://www.electronicplus.com/images/products/FLG.jpg Picture of a
cold cathode lamp

http://www.electronicplus.com/content/ProductPage.asp?maincat=la&subcat=lcc
lamps and supplies

I do remember seeing one power supply in a catalog that was quite a
bit smaller and long and narrow. But it too was a bare circuit board
not a cylindrical device - and not in the current issue of my Jameco
catalog.

Electro luminescent "Wires" work on similar type supplies >90V high
frequency and low current.

Cold Cathode lamps are cylindrical and long like a pencil from about
3/16" diameter to 3/8" and 4" long to >12" long - wire on either end




There are high frequency high voltage supplies used for neon tubes
that aren't, strictly speaking, transformers. They are small and
light but not the size of a pencil.

How small? My recollection is of a small black cylinder with four wires
coming out of it.

Nope. Rectangular (the only ones I've seen) More like the size of an
duplex receptacle box with wires the size of pencils coming out of it.

These things work at an open circuit voltage of 12,000 volts at 100
KHZ - for that voltage and frequency you need a fairly thick
dielectric to prevent corona losses even if the dielectric doesn't
break down - so thick wire insulation, sturdy enclosures and potting
compound is the norm.

Don't know what else to offer. Search on power supplies for cold
cathode fluorescent lamps, electro luminescent wires, or solid state
neon tube drivers. All similar types of HV supplies.

In the case of neon tubes the things have to be able to drive ~300 +
watts at high voltage and frequency - can't be but so small . . .
--
.