Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.
My Hobby Website:
High volts for high amp efficiency ? - RF Cafe Forums
RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media
platforms dominating public commenting venues. RF Cafe Forums began sometime around
August of 2003 and was quite well-attended for many years. By 2010, Facebook and
Twitter were overwhelmingly dominating online personal interaction, and RF Cafe
Forums activity dropped off precipitously. If the folks at
phpBB would release a version with integrated
sign-in from the major social media platforms, I would resurrect the RF Cafe Forums,
but until then it is probably not worth the effort. Regardless, there are still
lots of great posts in the archive that ware worth looking at.
Below are the old forum threads, including responses to the original posts.
|-- Amateur Radio
Gripes & Humor
-- CAE, CAD, &
Test & Measurement
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