On 07/23/11 04:34 PM, jeff millar wrote:
> This email describes what I've learned from looking at these modern
> transistors
> for the last few months. It seems to me like a fundamental crossover point
> has
> been reached. Silicon processing technology has produced rugged VHF/UHF
> transistors, with reasonable impedance matching for a reasonable cost,
> especially considering all the other costs associated with an amplifier.
> These
> parts will only get better and cheaper as time goes on.
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.
--
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
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