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Anonymous Poster

Challenging the gurus/enthused purist. bridging the limits?

08/14/2007 8:23 PM

say you had a transformer with a ratio of 1 : 33.33

the AC supply is rated at 240V @ 10A.

I'm going limit your resistor choice to give you the use of 10 1KR resistors 5W, and a ship load of 3R3 1W resistors. can you design a series parallel network to output 8KV at 0.02A with the smallest possible amount of resistors?

this is just a brain teaser, for the extra enthusiastic.

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Anonymous Poster
#1

Re: Challenging the gurus/enthused purist. bridging the limits?

08/14/2007 8:49 PM

No, it's impossible.

it is possible by concentrating on the amp output, the minimum limit of resistors, and the watt dissipation factor to arrive at the maximum voltage achievable.

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#2

Re: Challenging the gurus/enthused purist. bridging the limits?

08/14/2007 9:18 PM

The answer is 0 resistors.

Given the limited amount of information I would use the 1:33.33 step-up transformer on its own to give approximately 8000V (ignoring supply voltage fluctuations). The transformer is rated at say 200VA (so the voltage does not drop too much under load), allowing a load of around 8kV at 0.02A.

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#3

Re: Challenging the gurus/enthused purist. bridging the limits?

08/15/2007 12:56 AM

If I understand your teaser correctly, you don't need any parallel resistors. Why not just stick the 10 1kΩ resistors and 118,182 of the 3.3Ω resistors in series?

You need 400kΩ and this will give you a nominal 400.0006kΩ, way better than the possible tolerances on your setup.

The dissipation of the resistors will also be way below your given watt ratings.

Jorrie

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#4

Re: Challenging the gurus/enthused purist. bridging the limits?

08/16/2007 3:12 PM

Hello,

I don't think you can get there from here. All transformers have at least some regulation; thus the output of your transformer will be below 8000V at all times.

Tom

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