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Re: Tool Steel's

Original poster: Bert Hickman <bert.hickman@xxxxxxxxxx>

Tesla list wrote:

Original poster: Ed Phillips <evp@xxxxxxxxxxx>
Hey Glen...
"oxidation" is going to occur on any type of metal used in a spark gap... the reason we use copper is for the cooling properties and electrical conductivity. Other metals cool alot slower than copper and eventually will become hot enough to maintain an arc alot longer then copper. The voltages used in a sparkgap are high enough to destroy almost anything conductive ( not too sure about diamonds tho) save the money and use the copper :)
Scot D"
Many of the spark gaps used in "wireless telegraphy" had electrodes made of zinc. Don't know its relative merits but copper was probably no more expensive so "there must have been a reason" - maybe.


Per Zenneck's excellent book ("Wireless Telegraphy", page 16), a spark gap between zinc electrodes had a lower equivalent "gap resistance" than an identical gap between copper electrodes in a simple LC circuit. Zinc (and magnesium!) gaps were therefore considered to be less lossy.

However, because of the additional metal vapor in the gap, zinc electrodes likely also resulted in poorer quenching (than gaps made from copper) when used in coupled LC circuits.

BTW, a scanned copy of Zenneck's 1915 book can be obtained in its entirety through the Internet Archive'a Million Book project. The DjVu file is about 52 MB:

Best regards,

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