[Milsurplus] Mica capacitor identify.. more

[J Forster]

Google finds:

Date:                           Mon, 26 Feb 2001 21:59:32 -0500
   Reply-To:                           "Kenneth D. Grimm, K4XL" <[log in to
unmask]>
   Sender:                           Boat Anchor Owners and Collectors List <[log
in to unmask]>
   From:                           "Kenneth D. Grimm, K4XL" <[log in to unmask]>
   Organization:                          BoatAnchor Manual Archive
   Subject:                           Re: How to read postage-stamp micas (not
the color dots)
   Comments:                           To: Mike Silva <[log in to unmask]>


  Mike Silva wrote:

  > I've got some postage-stamp micas that have their values indicated via text >
rather than color dots, and I don't know the
  code (except I can figure out > the mmf's). Some examples: > > CM35E 103 JN3
(0.01 uf) > CM30F 242 JP3 (2400 mmf)
  > CM35F 103 GP3 (0.01 uf) > > It's the CM stuff and the JN/JP/GP stuff I don't
know. Checked some ARRL >
  handbooks from 1950 to 1980 and didn't see anything. Mostly I care about > the
voltage ratings. Thanks!

  These three caps are marked according to Mil-C-5C standard of the 50s-60s. The
CM indicates "capacitor, mica." The 35
  simply designated that it was mounted using leads. I believe that the next
number was the voltage rating with E being 600volts
  and F being 1000volts. Then the capacitance, followed by the J for capacitance
tolerance of 5% or G for 2% or K for 10%
  or F for 1%. The next letter designated the operating temperature range with
M=-55C to +70C, N=-55C to +85C,
  O=-55C to+125C and P=-55C to +150C. The final number was either a 1 or a 3
indicating a "vibration grade" of either 10
  to 55cps or 10 to 2,000cps. CC caps were ceramic and CN were molded paper
dielectric caps. The numbering systems
  were similar. My memory is a bit fuzzy on some of the mil numbering systems,
but this is close if not exact. Hope this is of
  interest. Perhaps it will inspire someone to check what I have remembered and
fill in the gaps.

  Ken K4XL [log in to unmask] *** BoatAnchor Manual Archive *** On the web at
http://bama.sbc.edu or FTP site info:
  bama.sbc.edu login: anonymous p/w: youremailadr

-John




Glenn Little WB4UIV wrote:

> Rick
>
> The Mil Spec that covered this capacitor was MIL-C-5/10. This has been
> canceled. The basic MIL Spec is available here:
> <http://www.dscc.dla.mil/Programs/MilSpec/ListDocs.asp?BasicDoc=MIL-C-5> .
>
> My take on this is that this is a 0.039 MFD capacitor, +/- 5%, temperature
> rating of -55 to +85 degrees C, The voltage does not decode and is probably
> 100 VDC, it appears to have a temperature coefficient of -20/+100 ppm /
> degree C +/- (0.1%+ 0.1 pF).
>
> Hope that this helps some.
>
> 73
> Glenn
> WB4UIV
>
> At 01:21 PM 05/26/07, Rick Brashear wrote:
> >I just discovered a couple of Cornell Dubilier mica capacitors in the bottom
> >of a drawer, however, they are unmarked in the normal sense.  I can measure
> >them, but I need to know what they are supposed to be before that makes any
> >sense.  Each have the following printed at the bottom of the case:
> >CM6OE393JN1.  Does that mean anything to anyone?  Is that a 39000 pf?  How
> >about voltage and amperage rating, they are Type 9 mica caps?
> >
> >Thanks,
> >Rick
> >
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