[Elecraft] Differences between disc ceramic and blue plastic caps?

[Doug Person]

I understood the markings.  I just had misgivings about the equivalence 
of the plastic blue caps and the disc ceramic NPO types that I am more 
familiar with.  I do find the near microscopic print on these little 
caps to be quite a challenge - even with a large magnifying glass.  I 
can hardly imagine what lies ahead with SMD's - which will surely 
replace all these through-the-hole type components.  Presumably my new 
SMD soldering station will include a microscope along with the robotic 
articulated digits to manipulate the components.

73,
Doug -- KØDXV

Don Wilhelm wrote:
> Doug,
>
> Component markings have changed a lot over the years.  I would suggest that
> you refer to the information in the ARRL Handbook on component markings for
> an update on the various markings that are in current (and older) use.
>
> Yes, a capacitor marked '470' is a 47 pf capacitor.  The little blue (or
> yellow) ones will do just fine.  The old disc ceramics with the black mark
> on the top are NPO type, which has the same thermal characteristics as the
> 'C0G' type.
>
> It is not good practice to try to identify a component by its color - that
> could change at the whim of the manufacturer, learning the current markings
> for components is the only way I know to be certain about the designations.
>
> 73,
> Don W3FPR
>
>   
>> -----Original Message-----
>>
>> I'm went looking for a 47pf cap for C73.  Naturally, (probably because
>> I'm an old-timer, ya know - kits from Knight-Kit, Johnson, WRL, Ameco,
>> not to mention the Benton Harbor stuff) I was looking for a disc ceramic
>> cap marked 47 with a black mark on the top.  Not finding any, I looked
>> through the parts list for the rf board where it indicated in might also
>> be marked 470 and be one of those little blue plastic caps. Just so I'm
>> sure before I solder these puppies in, C73, C20, C24, and C203 are OK as
>> little blue plastic caps marked 470, correct?
>>
>>     
>
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