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Jeff Liebermann Jeff Liebermann is offline
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Default gas discharge bulb V/I trace ringing?

On Thu, 6 Jul 2017 07:15:39 -0000 (UTC), frank
wrote:

I'll try to make a test setup with constant current on a GDT and try
to measure the frequency of the oscillation.
Frank


Could I trouble you to disclose the maker and model of the gas
discharge transient suppressor that you're testing, and the model
number of the Heathkit curve tracer? I don't have a curve tracer but
I do have a high voltage variable power supply that I can manually
sweep to see if there are any negative resistance regions.

The manufacturers of gas discharge tubes should have something on the
gas discharge tubes and negative resistance.
http://www.littelfuse.com/~/media/electronics/product_catalogs/littelfuse_gdt_catalog.pdf.pdf
Yep, the graph looks much like a neon lamp. The tube triggers at 75
to 600VDC, and rapidly drops to 15VDC.

I have a different guess(tm). When the gas discharge tube conducts,
it effectively shorts the terminals of the device. I don't think your
Heathkit curve tracer will not like a short circuit. It should have
some kind of short circuit or overcurrent protection circuit which I
would guess(tm) is doing the oscillating. Insert a large value
resistor in series with the gas discharge tube and try again.

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