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Re: MMC dissipation factor measurement

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Terry,

On 16 May 2002, at 21:13, Tesla list wrote:

> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> Hi All,
> The question comes to me tonight....
> I have a TEK 3012 scope.  I have a TEK 5100 voltage probe, lots of Pearson
> current monitor CTs...  I have a lot of sine wave generators with low
> impedance...  Like 350kHZ at 5 amps...
> So, would I have any chance "in the hot place" of measuring the dissipation
> factor of a poly MMC cap?  Like <0.001 dissipation factor...
> I guess I would have to detect the difference between 90 degrees and
> 89.87856 degrees to find the dissipation factor...
> Sounds doable but maybe someone out there has "been there, done that..."  I
> was just asked the question and "I" have not thought much on it cause I am
> sleepy :o)  Might need a step down transformer to get a really low source
> Cheers,
> 	Terry

You may be able to do it on an incremental basis using bridge 
techniques. I am suggesting measuring the difference between two 
different types of capacitor, the one with the lowest esr score then 
going on to be the standard for a succeeding test which compares 
another. Hazy I know.