Re: HV Measurement - The Divider Problem (fwd)

[<sroys@xxxxxxxxxxxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 23 Sep 2004 08:32:09 +0930
From: Matthew Smith <matt@xxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: HV Measurement - The Divider Problem (fwd)

Peter Terren wrote:
<blockquote>
If you had an open circuit in the chain, then this would explain all your
readings and the demise of your meter.
Was it a 50Hz supply or a flyback because the spiky nature of the latter
will give low rms or standard voltage readings despite the high peak
readings (which is what blows the meter).
</blockquote>

Seems like the problem was my failure to take the meter input impedance into 
account.

For the record, the supply was a TV horizontal drive transformer (*not* the line 
out transformer) wired backwards and feeding a three-stage Cockroft-Walton 
multiplier, charging a 250nF/5kVwkg capacitor.

I was actually testing the capacitor, to see how long it held its charge after I 
turned the supply off.  The answer, before that fateful bang, was very quickly. 
  I should have used my electrostatic meter as the 330M of the divider seemed to 
make a rather good bleeder resistor...

Cheers

M

-- 
Matthew Smith
Kadina Business Consultancy
South Australia