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Re: [Amps] New NXP BLF578XR 1200W LDMOS FET is "indestructible"

To: amps <amps@contesting.com>
Subject: Re: [Amps] New NXP BLF578XR 1200W LDMOS FET is "indestructible"
From: Ron Youvan <ka4inm@tampabay.rr.com>
Reply-to: ka4inm@tampabay.rr.com
Date: Sat, 13 Aug 2011 08:53:13 -0400
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Dr. David Kirkby wrote:

> These is an equation, based on the physics of semiconductors, that shows:

> P f^2 R = constant.

> P = power
> f = frequency
> R = output impedance

> I can't recall the derivation of that, but could dig it out. (It was one of 
> the
> things I learned while doing an MSc in microwaves and optoelectronics)

> So basically doubling the frequency, you are going to only get one quarter of
> the power for the same output impedance.

> I don't know how close we are to the theoretical limits of what is possible, 
> but
> perhaps not too far.

   I've never heard of this, but I see no theoretical limit problem, we can 
tolerate any output 
impedance if we are allowed to use a transformer/s.
-- 
    Ron  KA4INM - I've been carving my initials on trees and furniture all my 
life
                  'course I didn't use my own initials, I'm not stupid ... Earl 
Pitts 4-2-9
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