Message-ID: <002201c88130$50f2c580$0e00000a@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
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> <004301c88122$618a8bc0$0900a8c0@Lark>
Date: Sat, 8 Mar 2008 15:22:49 -0000
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Subject: Re: LF: Re: Smaller DC feeding choke in class E amplifier
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Ok Alan,

Ok , no problem on the  'isolation'  using a inductor , I was thinking more 
of the power supply demand/regulation side of things , looks like these 
things are a bit tricky to  feed 'dc' interms of peak demand on the suppy 
... this slides into  calcuations of actual power supplied, form factors etc 
, these must affect power supply design in terms of regulation bandwith , 
parasitic inductance etc ? , that was the link to mobile phones !

G ..



----- Original Message ----- 
From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Saturday, March 08, 2008 1:40 PM
Subject: Re: LF: Re: Smaller DC feeding choke in class E amplifier


> 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
>> >
>>
>>
>>
>
>
>
>
>
> -- 
> 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
>
>