Re: Build own capacators

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Original poster: "James Zimmerschied" <zimtesla@xxxxxxx>

Ed,
the mica caps were 5 strings of 5 in series. Nominal 0.01 microF each 
but measured around 0.009 microF in the MMC. They are Sangamo 
Electric Co CM60B103K TYPE A2 if any of that is significant.

The barium titanate caps I borrowed are being used in a medium sized 
coil (Bob Svangren's) which has been operational for over 10 yrs and 
has many runs in the 3-5 minute range. It seems they warm up a bit 
and change value a little but seem to be holding up for Bob. His PT 
powered coil puts out 72-84" streamers. I believe he is using 0.054 
microF total in his cap bank.

Regards,
Jim----- Original Message -----
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Sent: Saturday, December 17, 2005 12:50 PM
Subject: Re: Build own capacators

Original poster: Ed Phillips <<mailto:evp@xxxxxxxxxxx>evp@xxxxxxxxxxx>

As a final test I used a 0.009 microF MMC made up of mica caps (2500
VDC 0.01microF). These gave less spark length than the other types I
tried (11" vs 16")."

    How many of those 0.01 ufd capacitors did you use in series
parallel to get 0.009 ufd?  I'm surprised at your results as mica
capacitors have always worked very well here and were the norm in
high-power spark transmitters.  I use barium titanate capacitors as a
rule, because of their small size and low ESR, but they're lossy and
can't stant more than perhaps 30 second runs without puncture.  Spark
length seems as good as mica.

Ed