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Date: Thu, 09 Aug 2012 02:36:20 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: Caps for Class-E amp
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Am 09.08.2012 02:24, schrieb Dimitrios Tsifakis:
>
> What is the VDC rating of the FKP1 caps in your 1 kW PA?
>    

It is a mixture because i had only a few pieces on hand. If i remember 
correctly the lowest DC voltage is 1.25 kV.


>
> Output impedance is about 1.4 ohm. I have designed it to produce 50 W
> at 12 V and of course 200 W at 24V.
Yes, good idea. In /p for moderate power and at home in QRO :-)

>   I work in multiples of 12 V as I
> normally use big SLA batteries to power my equipment. The FET is a
> monster IXYS 500V/55A FET which should be bombproof.
But you could have much lower on-resistances when using a 100V FET. 200W 
at 24V is no problem though. IXYS is mostly a good choice. But quite 
expensive. Once you lost a pair of them you begin to think to go back to 
the IRFP types, at least i have done so ;-)

> I do know that things are probably simpler if I select a higher
> voltage supply as that will increase the output impedance and make
> life a bit easier on the poor capacitors. But I do want to be able to
> operate it out in the field and not carry half a truck worth of
> batteries :-)
>    
:-) I can fully understand that.
In my first Lf /p experiments i used this 1 kW PA and run it on 12V or 
24V or 36V, using batteries in series. But it should be no problem to 
get a good efficiency even at 12V DC, at least for a 100W PA.

>   In any case, I don't want to go more than 200 W as I am scared of the
> voltage developed across my loading coil (currently about 12 mH or ~10
> kohm XL).
>
> 73, Dimitris VK1SV/SV1DET
>    

73, Stefan/DK7FC