[Amps] Doorknob capacitors

gdaught6 at stanford.edu gdaught6 at stanford.edu
Wed Mar 21 21:08:16 EST 2007


On 21 Mar 2007 at 17:10, Larry Benko wrote:

> Is there any reference someone could point me to concerning general 
> ratings for doorknob type capacitors.  I have several that are about 
> 1.25 inches in diameter and 1 inch long with values of 270pF and 400pF 
> and DC ratings of 12KV and 20KV.   I assume at RF the most important 
> rating would be the rated RF current which based on the dissapation 
> factor of the cap. would be basically how much the capacitor would heat 
> up.   What would be typical RF current ratings for capacitors such as 
> these be?  I was planning on using a couple as extra fixed capacitance 
> in a couple of L network tuners I am building.  One reason to minimize 
> much heating is that the capacitors hava a fairly significant negative 
> temperature coefficient.

Tony, I0JX, has a good discussion of this subject at:

http://www.geocities.com/SiliconValley/Pines/5440/index.html

go down the list 6 or 7 lines, and you'll find lots about capacitors 
in RF circuits.

73,

George T. Daughters, K6GT






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