Re: SS NST--Good for anything?

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Original poster: "Justin Hays by way of Terry Fritz <twftesla-at-qwest-dot-net>" <pyrotrons2000-at-yahoo-dot-com>

Hi All,

> i bought a 15kv 20ma at 20khz solid state neon transformer off 
> ebay. i made a voltage divider with a couple of 1 meg resistors and

> looked at it with an oscilliscope. i was suprised to see that the 
> voltage was sinusoidal. why is it sinusoidal? i was guessing it 
> would be square wave or maybe a pretty low voltage with high 
> voltage spikes, like in a flyback transformer. if it uses resonance

> for at least some voltage gain it would be a sine wave but i dont 
> see how else it could put out sine waves(except for wasting a bunch

> of energy in the switches).

Although I'm sure the circuits vary from manufacturer to
manufacturer, the ones I've seen are half-bridges that hard switch
the primary of a HV stepup transformer. Of course, like any switcher,
the output (of the bridge!) is a square wave to minimize 1^2
(heating) losses in the transistors. 

Remember, just because the output looks like a sine wave doesn't mean
that it's input is a sine wave.

On a different note, what you're looking at may or may not be a true,
formed with resonance, sine wave. The shape can be hard to
distinguish sometimes...I notice that the output of my SS neon
transformer is something like a rounded-off triangle wave. Along
those lines, I can't measure DC resistance across the output of my SS
neon....which probably means there is a series HV capacitor in there
somewhere.......which explains the rounded-off looking triangle wave.


Neat little circuits....I could power a TC with mine as the output
can be shorted with no problem.

Take care,

Justin Hays
KC5PNP
Email: justin-at-hvguy-dot-com
Website: www.hvguy-dot-com

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