[ARC5] [Boatanchors] Postage Stamp Mica Question

[Richard Knoppow]

     Micamold paper caps have a silver or white dot somewhat isolated from the others but seems to follow this rule.  The JAN and RMA color codes are shown in nearly all equipment handbooks starting from about 1940.  They can also be found in the ARRL handbook and other sources such as the ITT book _Reference Data for Radio Engineers_.  There are at least four variations of the dot code for "postage stamp" caps including a single-row with three dots. 

     

-----Original Message-----
>From: "David C. Hallam" <dhallam at knology.net>
>Sent: Aug 9, 2013 4:22 PM
>To: jfor at quikus.com
>Cc: boatanchors at mailman.QTH.net, ARC5 at mailman.QTH.net, ArmyRadios at yahoogroups.com, Milsurplus at mailman.QTH.net, boatanchors at puck.nether.net, Vintage-Military-RADAR at yahoogroups.com
>Subject: Re: [Boatanchors] Postage Stamp Mica Question
>
>The 6 dot AWS/JAN color code used the upper left hand dot as a marking 
>for mica or paper.  The black dot means mica.  A silver dot means paper. 
>  There were paper capacitors in molded cases just like the micas.
>
>David
>KW4DH
>
>On 8/9/2013 5:57 PM, J. Forster wrote:
>> Hi,
>>
>> I'm still working on the ART-4 transmitter and want to put values on the
>> schematic. The unit has about a half dozen 'postage stamp' mica caps.
>>
>> They are all marked like 'Type 5' on thos page:
>>
>> http://www.radioremembered.org/capcode.htm
>>
>> and have 6 color dots.
>>
>> Reading in the correct order, clockwise starting at the top left, the dots
>> are:
>>
>> Black
>> Green
>> Brown
>> Black
>> Yellow
>> Red
>>
>> See the issue? The value SEEMS to be 051 pF; 400 VDC, 2%
>>
>> Question:  Was it ever convention to use a leading zero in color codes for
>> this type of cap? I've never seen it before.
>>
>> Thanks,
>>
>> -John
>>
>