Return-Path: Received: (qmail 80101 invoked from network); 18 May 2004 23:35:30 -0000 Received: from unknown (HELO ptb-mxscan03.plus.net) (212.159.14.237) by ptb-mailstore04.plus.net with SMTP; 18 May 2004 23:35:30 -0000 Received: (qmail 65528 invoked from network); 18 May 2004 23:35:30 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from ptb-mxcore03.plus.net (212.159.14.217) by ptb-mxscan03.plus.net with SMTP; 18 May 2004 23:35:29 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore03.plus.net with esmtp (Exim) id 1BQE7M-000GoH-Qp for dave@picks.force9.co.uk; Wed, 19 May 2004 00:35:28 +0100 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1BQE6b-0006Yt-9L for rs_out_1@blacksheep.org; Wed, 19 May 2004 00:34:41 +0100 Received: from [213.232.95.59] (helo=relay.salmark.net) by post.thorcom.com with esmtp (Exim 4.14) id 1BQE6a-0006Yk-Mx for rsgb_lf_group@blacksheep.org; Wed, 19 May 2004 00:34:40 +0100 Received: from imo-m26.mx.aol.com ([64.12.137.7]) by relay.salmark.net with esmtp (Exim 4.24) id 1BQKf8-00029p-Mu for rsgb_lf_group@blacksheep.org; Wed, 19 May 2004 07:34:46 +0100 X-Fake-Domain: G0MRF@aol.com Received: from G0MRF@aol.com by imo-m26.mx.aol.com (mail_out_v37_r1.3.) id l.cf.cfcb472 (3940) for ; Tue, 18 May 2004 19:34:25 -0400 (EDT) From: G0MRF@aol.com Message-ID: Date: Tue, 18 May 2004 19:34:25 EDT To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 X-Mailer: 8.0 for Windows sub 670 X-Spam-Score: 2.3 (++) X-Spam-Report: autolearn=no,DATE_IN_PAST_06_12=0.599,HTML_MESSAGE=0.001,HTML_TAG_BALANCE_HTML=0.411,MAILTO_TO_SPAM_ADDR=1.052,NO_REAL_NAME=0.285 Subject: Re: LF: output transformer problems Content-Type: text/html; charset=windows-1252 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.7 required=5.0 tests=HTML_MESSAGE, HTML_TAG_BALANCE_HTML,MAILTO_TO_SPAM_ADDR,NO_REAL_NAME 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-PN-SPAMFiltered: yes X-Spam-Rating: 1 Content-transfer-encoding: 8bit In a message dated 5/18/04 9:19:13 PM GMT Daylight Time, knaap159@zonnet.nl writes:

Wonder what current I should have when applying lower supply voltages
to the FET's.
For example. what currents to others have at 15V or 20V or so.

73, Dick, pa4vhf




The amplifier follows the standard relationship of output power to supply voltage.
i.e.  Twice the voltage will give four times the output power.

If you are using voltages much lower than 28V then you can increase the secondary turns or decrease the primary winding to compensate.

Removing the diodes will cause a negative voltage pulse on the FET gates as they has now lost their low impedance reference to ground. This may or may not be a problem.

Good luck

David