I helped on ARF with reply; 0.0039 uF mica. Uses the old obsolete 6-dot color code.
Chuck
Peter. it's a mica, obsolete 5-dot color code. I can't determine value from the colors in the picture. Measure it. Probably reads good and works ok regardless if you don't know intended value. What's on the schematic? If it is in a radio and you are fixing it just leave it in. If radio works and you are happy that's it.
Bill VA
I got to refresh once in awhile. I don't see six dots Chuck.
Bill VA
Well I only see 5 dots
and I read the top 3 colors as brown-white-green (1-9-5)
...to me that was 1- 9 and five zeros.... maybe
I didn't know what to make of the bottom row... left dot brown and right dot nothing!
so some how that "seemed" like 1 900 000 'something'
My capacitance meter read it as 1.9-nano farads = .0019uf ....or very close to a .002uf cap
Then I compare-tested on my meter with a .002-uf cap.. and when measuring a .002 uf cap ... of course it read the same on my meter as 2-nano farads
Now... on the other hand ...maybe the dots really means 195 with 1 zero from the bottom row brown dot
....or 1950pf = .00195uf... or 1.95 nano farads... or very close to .002uf
Who really knows for sure... ?? lol
This cap was in the local osc circuit for the 2-7mhz band
So...I replaced it with a .002uf and the oscilator seems to run fine.
Here's a clearer cleaned up image:
http://www.pbpix.com/square-cap2.jpg
I was wrong too Bill, as it turns out (see ARF thread). The obsolete 6-dot code I found does place significance on "no-dot" in the center bottom row of dots as meaning 20% tolerance. That's why I erroneously picked it a making most sense to me.
Scratched my head long on this one too. 5-dot? 6-dot? 5-dot? Chuck
Well Chuck after I had posted about not seeing the 6 dots I had second thoughts. I had to go out to the shed and revisit my references. Your "blank" started to sound good. I checked some old caps I had and some are new old stock. I believe the dot impression was to be molded into the caps as part of the standard. I don't have any thing to back that up other than that's the way it appears. Makes sense. So a six dot cap with a blank color in the middle of second row is five dot coded. No wonder they became obsolete. As you know, regardless of the number of dots, manufacturers later used their molds and stamped the value or just put on the additional colors. I have examples of Sangamo five dot, three on one side, two on other, with stamped value. And others where they just made a second row under the top row by just stamping on the colors, no recessed dot there. These were the Jan type. Solar used their different molds too but apparently only stamped the value, no color at all. Aerovox produced some of the best colored Jan ones with value stamped on the back. Most of the Micas I have ever tested read good. Reading the color gets tedious for me. I thought the orange was orange too. By the time I did some math on moving that decimal around I had that sucker reading in whole number MF's! So what is that multiplier color on Peter's cap? I see Dave came over and confirmed his reading.
Bill VA
Dave
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:I have no clue what the heck the value of this cap is or even if it's mica or not.
:Any help guys?
:http://www.pbpix.com/square-cap.jpg
The cap is an El Menco brand.
You'd think we should be able to find the El Menco color dot system documentation somewhere... lol
Well doesn't really matter... normally if I DO have the schematic I don't fear... but here I was guessing.
Thank you all