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| Function of a three-terminal spark gap |
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| T3sl4co1l:
Oddly, the pointy electrode design predisposes it to corona discharge, making it less reliable as a measurement tool (besides all the problems with atmospheric discharge in the first place). Tim |
| floobydust:
In one science paper, the teaser electrode arc was said to emit UV which would then start the main arc. So I tried pointing a UV LED at a spark gap and it hardly makes a difference in breakdown voltage. Thought maybe one could make a light activated spark gap. Something good for transient generators, ESD guns etc. |
| T3sl4co1l:
Or if not the air, then the work function of the electrodes. Which will be pretty high if made from common metals. Hm, I don't know offhand if there are even any air-stable metals, intermetallic alloys, or compounds (oxides, sulfides, etc.) that have a work function lower than the ionization potential of molecular oxygen (i.e., ca. 250nm UV). Tim |
| MagicSmoker:
--- Quote from: floobydust on October 05, 2019, 05:45:55 am ---In one science paper, the teaser electrode arc was said to emit UV which would then start the main arc. So I tried pointing a UV LED at a spark gap and it hardly makes a difference in breakdown voltage.... --- End quote --- The wavelength needs to be closer to the mercury line (254nm, UV-C) to reliably initiate ionization in the gap and almost all UV LEDs emit in the long end of UV-A (~400nm) which is only good for making fluorescent things glow in the dark. |
| Gyro:
UHP Mercury vapour projector lamps use an optically coupled separate UV (<270nm) corona discharge cavity to initiate the discharge in the main (>200 bar pressure) chamber... https://www.lightsearch.com/pdf/uhp.pdf |
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