Electronic NST waveforms

[Marshall Dudley]

Does anyone have any information or know a link on the specifications
and characteristics high frequency electronic neon sign transformers? I
have an unusual application where I need an AC square wave of around
3-4KV with a dwell time between the pulses. From looking at the limited
specifications from some of these units it appears that is what they
produce, but I can find no information on the actual peak amplitude vs
their "rms" equivalent amplitude (they will not be the same if there is
dwell time), on/off or dwell ratio, and method of current limiting (drop
in voltage or reduction in "on" time). Also their specifications make
no sense, for instance the one limited specification I could find claims
that a 3 KV RMS unit has about a 4.5 KV peak to peak voltage, which is
impossible, a square wave which would have the lowest ratio would be 6.
KV peak to peak.

Thanks,

Marshall

 

[Robert Baer]

Does anyone have any information or know a link on the specifications
and characteristics high frequency electronic neon sign transformers? I
have an unusual application where I need an AC square wave of around
3-4KV with a dwell time between the pulses. From looking at the limited
specifications from some of these units it appears that is what they
produce, but I can find no information on the actual peak amplitude vs
their "rms" equivalent amplitude (they will not be the same if there is
dwell time), on/off or dwell ratio, and method of current limiting (drop
in voltage or reduction in "on" time). Also their specifications make
no sense, for instance the one limited specification I could find claims
that a 3 KV RMS unit has about a 4.5 KV peak to peak voltage, which is
impossible, a square wave which would have the lowest ratio would be 6.
KV peak to peak.

Thanks,

Marshall

1) All modern electronic neon xfmrs i have seen have symmetrical output,
that is, it is a CT output with the tap to ground.
2) The modern electronic neon xfmrs use switching for conversion of a
rectified power line, so i expect that the output to be a squarewave;
*no* "dwell" time engineered in.
3) All neon transformers have a design similar to CFL electronic
supplies, in that they are designed for constant current; the high
voltage is to "merely" break down the gas at start-up.
Remember, once neon has been ionized, the voltage seen across it will
be about 65V (am partly guessing, been a long time since i looked it up
in the Chem Rubber Handbook of Chemistry and Physics).
4) If you really want to know, then take the transformer and sign *set*
(yes, they are "matched") and a high voltage probe and look at one end.