Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
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Below are all of the forum threads, including all
the responses to the original posts.
Post subject: High volts for high amp efficiency ?
Unread post Posted: Thu Feb 03, 2005 8:06 am
From say 100 MHz
to 1GHz I would imagine that operating RF amplifiers with a higher supply
voltage should result in higher efficiency. My reasoning is pretty simple.......
Higher Volts must mean lower currents for a fixed output power, where
I assume that the majority of loss is due to I squared R. Anyone care
Of course, unless you happen to get just the right
impedance with the chosen rail and output power you will need to impedance
match. It may be the case that a lower supply rail would mean you could
do away with the match and reduce losses incurred in this part of the
We then get into greater detail with just where the
transistor is operating (with regard to saturation). Not to mention
those funny games you can play with harmonic terminations and switching
classes such as class E but to keep the discussion simple lets ignore
these for now.
In any case, even if high volts does gain you
somthing the chances of building anything seem slim to me as I find
that most of the new transistor stuff around is aimed at low supply