Return-Path: Received: from rly-da08.mx.aol.com (rly-da08.mail.aol.com [172.19.129.82]) by air-da07.mail.aol.com (v126.13) with ESMTP id MAILINDA074-a874b0f008ab7; Thu, 26 Nov 2009 17:26:40 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-da08.mx.aol.com (v125.7) with ESMTP id MAILRELAYINDA087-a874b0f008ab7; Thu, 26 Nov 2009 17:26:19 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NDmlj-0000ZJ-0g for rs_out_1@blacksheep.org; Thu, 26 Nov 2009 22:24:55 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NDmli-0000ZA-DR for rsgb_lf_group@blacksheep.org; Thu, 26 Nov 2009 22:24:54 +0000 Received: from smtp-vbr15.xs4all.nl ([194.109.24.35]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NDmlh-0004Kg-M5 for rsgb_lf_group@blacksheep.org; Thu, 26 Nov 2009 22:24:54 +0000 Received: from LAPTOP (a83-163-2-28.adsl.xs4all.nl [83.163.2.28]) by smtp-vbr15.xs4all.nl (8.13.8/8.13.8) with SMTP id nAQMOlLv098828 for ; Thu, 26 Nov 2009 23:24:53 +0100 (CET) (envelope-from misan@xs4all.nl) Message-ID: From: "M. Sanders" To: References: <000e01ca6e84$d86c8710$0301a8c0@your91hoehfy9g> Date: Thu, 26 Nov 2009 23:24:49 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Virus-Scanned: by XS4ALL Virus Scanner X-Karma: unknown: X-Spam-Score: 3.4 (+++) X-Spam-Report: autolearn=disabled,FORGED_MUA_OUTLOOK=3.36,HTML_MESSAGE=0.001 Subject: LF: Re: CLASS E Content-Type: multipart/alternative; boundary="----=_NextPart_000_0024_01CA6EEF.A608BCB0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.4 required=5.0 tests=FORGED_MUA_OUTLOOK,HTML_30_40, HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0024_01CA6EEF.A608BCB0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Mal an all LF, I have built an Class-E 100W amp for 136kHz at approx 85%-90% efficien= cy at 12VDC with two IRF fet's parallel some time ago. The capacitors= used in the output circuit were somwhat large to transform the low im= pedance at the FET output towards the aearial output socket at 50Ohms.= For DC separation an elco 450uF at 105degC (normally used in switchin= g PSU's) worked ok. The PI filter capacitors high voltage type worked= fine (did not get hot). PI filter L is 10uH air wound with a ferrid= rod partly inside moving back/forward inside the coil for tuning the= amp at exactly class-E phase shift and compensating the aereal impeda= nce, not beeing exactly 50 ohms in practice of course. Any iron near= the coil melts! so use only copper/brass materials there. The first pair of fets have been blown up by not switching the gate fu= lly in voltage. No fet will survive if DS is not turned fully open ins= tantly. Normal DS resistance at Vgate > 2V is below 0.3Ohm, power dis= sipated within fet specs at class-E. At Vgate below 2V the Pds=3DVds*I= ds at the phase shift that works for class E will destroy any fet. Slo= ppy gate switching / driving the class-E wit a sine-wave and you're up= for trouble sooner or later (aereal 50Ohm mismatch).=20 Kind regards, best 73's, Mike, PC4M=20 ----- Original Message -----=20 From: mal hamilton=20 To: rsgb=20 Sent: Thursday, November 26, 2009 11:40 AM Subject: LF: CLASS E MF and Co Getting suitable capacitors is the problem, not normally available= from the junk box. Maybe a class F amp is the answer or the mechanical G turbo charged= rumoured to be over 100% efficient G3KEV ------=_NextPart_000_0024_01CA6EEF.A608BCB0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hello Mal an all LF,
 
I have built an Class-E 100W amp= for 136kHz at=20 approx 85%-90% efficiency at 12VDC with two IRF fet's parallel some ti= me ago.=20 The capacitors used in the output circuit were somwhat large to transf= orm the=20 low impedance at the FET output towards the aearial output socket=  at=20 50Ohms. For DC separation an elco 450uF at 105degC (normally used in= switching=20 PSU's) worked ok. The PI filter capacitors high voltage type  wor= ked fine=20 (did not get hot). PI filter L is 10uH air wound with a ferrid ro= d partly=20 inside moving back/forward inside the coil for tuning the amp at= exactly=20 class-E phase shift and compensating the aereal impedance, not beeing= exactly 50=20 ohms in practice of course. Any iron near the coil melts! so use only= =20 copper/brass materials there.
 
The first pair of fets have been blow= n up by not=20 switching the gate fully in voltage. No fet will survive if DS is not= turned=20 fully open instantly. Normal DS resistance at Vgate > 2V  is= below=20 0.3Ohm, power dissipated within fet specs at class-E. At Vgate below= 2V=20 the Pds=3DVds*Ids at the phase shift that works for class E= will destroy=20 any fet. Sloppy gate switching / driving the class-E wit a sine-w= ave=20 and you're up for trouble sooner or later (aereal 50Ohm=20 mismatch). 
 
Kind regards, best 73's,
 
Mike, PC4M 
 
 
----- Original Message -----
From:=20 mal=20 hamilton
To: rsgb
Sent: Thursday, November 26,= 2009 11:40=20 AM
Subject: LF: CLASS E

MF and Co
Getting suitable capacitors is the= problem, not=20 normally available from the junk box.
Maybe a class F amp is the answer= or the=20 mechanical G turbo charged rumoured to be over 100%=20 efficient
G3KEV
 
------=_NextPart_000_0024_01CA6EEF.A608BCB0--