
Repairing a vintage 40-kilovolt xenon lamp igniter - eaguyhn
http://www.righto.com/2020/03/repairing-vintage-40-kilovolt-xenon.html?m=1
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kens
Also see CuriousMarc's companion video, which shows how the spark gap works
with a coherer for primitive radio transmissions.
[https://www.youtube.com/watch?v=9zG_DlxyugQ](https://www.youtube.com/watch?v=9zG_DlxyugQ)
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peter_d_sherman
Excerpts:

"So where is the spark gap in this unit? It turns out to be the ceramic
cylinder. I opened up the cylinder and found a stack of eight metal disks with
(maybe) carbon electrodes in the center. The disks are separated by mica
washers to leave 0.33 mm gaps between each pair. This forms a series of 7 tiny
spark gaps.

This type of spark gap is known as a "quenched spark gap". Spark gap
transmitters were the first form of radio transmitter, used from 1887 to 1920.
They used a spark to transmit Morse code via radio waves (details). The
quenched spark gap was one type of spark gap used in these transmitters, as
shown in the diagram below.

 _By combining multiple small gaps, the quenched spark gap could cool off
efficiently._ "

[...]

" _Spark gaps generate radio waves across a wide spectrum_ ; inventor David
Hughes first noticed this interference in 1878."

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Animats
A similar circuit is in every plasma cutter.[1] For the same reason; you need
a high voltage pulse to ionize the working gas (usually air) and start the
arc.

[1]
[https://guelphweddingshop.blogspot.com/](https://guelphweddingshop.blogspot.com/)

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kens
If you used xenon as the working gas in a plasma cutter, would you essentially
have a xenon arc lamp?

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Animats
Yes.[1]

[1] [https://youtu.be/qUutgYBqSoI](https://youtu.be/qUutgYBqSoI)

(I miss the days of TechShop, when I had access to tools like that.)

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xfitm3
I miss TechShop, too. If making is your passion theres good news: it isn't
dead. Current virus issue excluded there are many smaller maker spaces you can
join in the bay.

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Animats
I have small tools. TechShop had the big stuff - CNC mills, waterjets, plasma
cutters. I used all of those. The smaller maker spaces are at the low-end 3D
printer level. Maybe a wood shop. There's Humanmade in SF, which has much of
the old TechShop gear, but it's an hour away and twice as expensive as
TechShop.

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userbinator
That schematic of a Tesla coil is the same as a spark-gap transmitter, except
of course the latter is designed to emit as much as possible and has an
antenna connected where the output torus would be; see page 375 of this
excellent book:
[https://archive.org/details/principlesunderl00unit](https://archive.org/details/principlesunderl00unit)

(Although very old, that book is great at explaining the basics of what radio
actually is.)

