Re: gEDA-user: OFF: capacitors for RF power amplifier

[John Doty <jpd@xxxxxxxxx>]

On Apr 11, 2011, at 9:55 AM, John Doty wrote:

> 
> On Apr 11, 2011, at 9:19 AM, Kovacs Levente wrote:
> 
>> On Mon, 11 Apr 2011 16:58:37 +0200
>> Uwe Bonnes
>> <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
>> wrote:
>> 
>>> What value do you need? Try NP0/COG type, even if substantial more
>> 
>> 120pf ... 1.5nF
> 
> Another possibility in that range is plastic "film" dielectrics rather than ceramic.

Oh, and one more issue. AC is much more stressful on a capacitor than DC. It's best to choose a capacitor with an AC voltage rating. If you can't, a common rule of thumb is to choose one with a DC voltage rating 3 times the AC RMS.

Classically, this has been an application for mica capacitors, but they're relatively rare these days.

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd@xxxxxxxxx




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