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Re: Undamped oscillations



Original poster: Ed Phillips <evp@xxxxxxxxxxx>

Thank you Ed for the reference to Marconi's "timed spark discharger".
Googling this I found an excellent page at
<http://hjem.get2net.dk/helthansen/marconi_tx.htm>http://hjem.get2net.dk/helthansen/marconi_tx.htm that goes into nice
detail about the operation of such hardware.  I'm still not sure that I
would call the result "undamped", but at least it is more or less CW.
I
wonder just what visibility Tesla had into the actual waveforms?

Regards, Gary Lau
MA, USA "

If there was one spark per cycle the wave would be undamped although there might be harmonics present of magnitude depending on the loaded Q of the circuit. If there was only one [correctly phased] spark every N periods then I believe a mistuned tank circuit would result in a broader wave although I've not tried to analyze the situation. As for Tesla's visibility he probably had only his intuition at the time (pre 1900). Cathode ray oscillographs didn't come along until several years later during Wardenclyfee days and no evidence he had on. Big, expensive, and awkward to use. Zennek's "Wireless Telegraphy" does have photographs of some waveforms, at least in the US edition I have. There's a nice little book called "WAVEFORMS" by a guy named V. I. Phllips (no relation) which reviews most everything which was used to try to view or measure or visualize waveforms, both acoustic and electrical, from the mid 19th-century on to the present and I have a copy [somewhere]. The date is from his book.

Ed