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Re: MMC

Hi,

I have 10 Meg resistors arcoss each cap in my MMCs.  My handheld LCR meter
has never been affected by the resistors.  It uses sine waves to measure
the capacitance.  Perhaps metters that use RC timing get confused with the
resistors added...

The capacitance function of many multimeters has never work worth a darn
for me.  The "real" LCR meters seem to do fine.  Some of them measure
dissipation too...  Unfortunately, hand held LCR meters usually cost a bit
more than a nice multimeter(~$200).

The B&K870 series and the Elnico LCR1801 (sold under many brands) work very
well and are fantastic to have for coiling.  Too bad they are all pricey...

Cheers,

	Terry


At 08:53 AM 02/07/2000 +1200, you wrote:
>Hi Herwig, all,
>
>
>> Original Poster: "Herwig Roscher" <herwig.roscher-at-gmx.de> 
>> 
>> 
>> Hi coilers,
>> 
>> After having assembled my new MMC I checked out the capacity 
>> of each string in order to monitor possible changes in the future. 16 
>> caps 100 nF connected in series (each of them paralelled by a 10 
>> MOhm bleeder) resulted in 7.0 nF. Strange, because the caps are 
>> tolerated +- 5%. I checked a single cap and the meter showed 150 
>> nF. I disconnected the bleeder and found the capacity to be 100 
>> nF. Correct! I used other type of meters and got different results.
>> 
>> Obviously the measured capacitance is dependent on the value of 
>> the bleeder and the meter's measuring method. So watch out!
>
>I ran into exactly the same problem when measuring some I built last 
>year. In the end, I resorted to resonating the finished articles with a 
>known inductance to derive their value.
>
>Regards,
>Malcolm 
>
References: