Re: Mini Transformers - Any good for Tesla use?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jan Wagner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jwagner-at-cc.hut.fi>

Hi,

On Sat, 17 May 2003, Tesla list wrote:
 > Original poster: "Chris Roberts by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <quezacotl_14000000000000-at-yahoo-dot-com>
 >
 > Hi everybody,
 > I have been thinking about making a micro spark gap coil and the hardest
 > thing is finding a micro sized power supply. I recently ran across some
 > small HV transformers on information unlimited's website that looked like
 > they might be useful,(
 > <http://www.amazing1-dot-com/voltage.htm>http://www.amazing1-dot-com/voltage.htm
 > scroll down to the bottom) the best one they have puts out 7000 volts at 10
 > ma, which would be perfect for something this small, but the output
 > frequency is around 30-50 khz. Anyone think these things could work even
 > though they are at such a high frequency? What would happen to the tank
 > capacitance? Thanks again.

Do you mean the thumb sized xfmr's at the bottom of the page? It's very
unlikely that these can supply 7kV 10mA (70W), they look more like a
corona wire HV supply from small laser printers. You could get more
powerful HV supplies than these for free from t.ex. old HP LaserJet
I/II/III units (power is ~5W, runs from 12V).

Odd btw that "Information Unlimited" doesn't give any information about
their product specs or what exactly you're bying... ;-)

Well, anyway, you could also make a very small yet medium power HV supply
using TV flybacks from small dead TV sets, or car ignition coils. You can
usually get these for free, and the driver electronics involved is quite
simple to build.

   www.google-dot-com  "ignition coil driver", "flyback driver"

If the output is >100Hz or so and the tank cap too large to be charged in
one AC cycle, then you need to rectify the HV supply output, using
ultrafast diodes. With a 20..30kHz supply it definitely has to be
rectified. A string of UF4007 (1kV 1A, ultrafast version of the
1N4007, about the same price, www.digikey-dot-com?) should do the job.

cheers,

  - Jan

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  Jan OH2GHR