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Re: [TCML] Re: Halfwave rectified Tesla coil and spark growth.


Mondo years ago I rectified a small TC that gave about 8 inch sparks. I used a string of about 40 TV flyback diodes, 13 kV and 3 mA continuous. They are about the size of 1/4 watt resistors. It worked for about a minute. We had it hooked up to a 12 inch sphere and it was just like a Van de Graaff generator. Then it quit. All the diodes were shorted.

The scheme would probably work with adequate diodes and maybe 20 M grading resistors and small caps. It should undoubtedly be potted. too. It would be fun to try it.


-----Original Message----- From: pterren@xxxxxxxxxxxx
Sent: Monday, April 15, 2013 10:55 AM
To: Tesla Coil Mailing List
Subject: [TCML] Re: Halfwave rectified Tesla coil and spark growth.

I rectified my briefcase Tesla coil which normally makes sparks of about 2.5
From the top of the Tesla coil is attached a string of 20 x 20 kV diodes
rated at 10 mA and with a fast recovery of 100 ns.
So theoretically rated at 400 kV (if under oil and with various other
The diode attaches to a string of capacitors rated at 56pF at 100kV. Each
ceramic cap is rated at 2.2 nF at 2.5 kV and there are 39 in the string.

With sparks across the diode (not across the capacitor) I should be
converting eg 50kV AC peak to a half wave 100kV DC (unsmoothed). The cap
charges to 50kV DC smoothed.
The half wave frequency is the same as AC.  I get sparks of around 3 inches
which is not bad considering the length of the diodes and cap is around 1
foot each have serious corona losses.

What are the implications for spark growth with half wave DC?
Has anyone else rectified a TC?

I only have pics and details on my new website - sadly still not activated
after 2 years.


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