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From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <47D1A6FF.1080803@telia.com> <00d001c8809a$71f10940$0900a8c0@Lark> <Pine.LNX.4.64.0803072006550.31396@plato.ucs.mun.ca> <001301c880b3$c8f8a9a0$0900a8c0@Lark> <000801c88111$a25c1530$0e00000a@AGB>
Date: Sat, 8 Mar 2008 13:40:39 -0000
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Subject: Re: LF: Re: Smaller DC feeding choke in class E amplifier
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Hi Graham, well there is not a lot of difference between "pulse amps" and
any other sort really from that point of view. The choke "opposes changes in
current" and also allows the signal to go to the load rather than be short
circuited by the PSU. At HF the situation is slightly different as you can
run into resonances as well, but as I understand most mobile phones use
Class E for efficiency and battery life in just the same way as we use 'em
on LF....that is if you ever switch em on (I hardly ever do !!) Being
digital they dont need to be linear.

Alan

----- Original Message -----
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
Sent: Saturday, March 08, 2008 11:43 AM
Subject: Re: LF: Re: Smaller DC feeding choke in class E amplifier


> Hi Alan,
>
> I never could get a handle on using passive components to  feed pulse amps
,
> a sort of
> contradiction ? what do  they do  in a mobile phone ?
>
> G ..
>
>
> ----- Original Message -----
> From: "Alan Melia" <alan.melia@btinternet.com>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Saturday, March 08, 2008 12:30 AM
> Subject: Re: LF: Re: Smaller DC feeding choke in class E amplifier
>
>
> > Hi Joe , Thanks for the "plug" :-))
> > Yes the circulating currents get pretty large with the low impednces
when
> > you try to put high power out with 12 supply. It doesnt do some caps a
lot
> > of good either (think of the current density in the thin foil!). Most of
> > my
> > tests were done at 35v or higher and that is a lot easier.
> > Best Wishes de Alan G3NYK
> >
> > ----- Original Message -----
> > From: <jcraig@mun.ca>
> > To: <rsgb_lf_group@blacksheep.org>
> > Sent: Friday, March 07, 2008 11:47 PM
> > Subject: Re: LF: Re: Smaller DC feeding choke in class E amplifier
> >
> >
> >> Alan, Johan and group,
> >>
> >> Since experimenting on LF I have discovered the joys of Class E,
> >> many thanks to Alan.  My first 100W TX used an IRF-640 as
> >> suggested on Alan's web page.  A dozen of them could be had for about
$10
> >> in 2003.  Unfortunately, they are have gone up quite a bit since then,
> >> although much cheaper than a 6146!   There seems to be a new generation
> >> of hexfet such as the IRFP260 and perhaps it might be possible to use
> >> this
> >> in a 12volt 100w amp.  Unfortunately, many  640's came to an untimely
> >> demise in my unsuccessful attempts to get 100 watts with a 12 V supply.
> >>
> >>
> >> 73
> >> Joe VO1NA
> >>
> >
> >
> >
> >
> >
> > --
> > No virus found in this incoming message.
> > Checked by AVG Free Edition.
> > Version: 7.5.516 / Virus Database: 269.21.6/1317 - Release Date:
3/7/2008
> > 08:15
> >
>
>
>