Envelope-to: dave@picks.force9.co.uk Delivery-date: Tue, 25 Oct 2005 04:31:57 +0100 Received: by pih-mxcore05.plus.net with spam-scanned (PlusNet MXCore v2.00) id 1EUFXY-00015z-6A for dave@picks.force9.co.uk; Tue, 25 Oct 2005 04:31:57 +0100 Received: from post.thorcom.com ([193.82.116.20]) by pih-mxcore05.plus.net with esmtp (PlusNet MXCore v2.00) id 1EUFXY-00015s-0d for dave@picks.force9.co.uk; Tue, 25 Oct 2005 04:31:56 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1EUFXL-00067I-Ok for rs_out_1@blacksheep.org; Tue, 25 Oct 2005 04:31:43 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1EUFXL-000679-CU for rsgb_lf_group@blacksheep.org; Tue, 25 Oct 2005 04:31:43 +0100 Received: from avmta4-rme.xtra.co.nz ([210.86.15.159]) by relay1.thorcom.net with esmtp (Exim 4.51) id 1EUGFu-0000hn-PK for rsgb_lf_group@blacksheep.org; Tue, 25 Oct 2005 05:17:48 +0100 Received: from mta3-rme.xtra.co.nz ([210.86.15.143]) by avmta4-rme.xtra.co.nz with ESMTP id <20051025033117.NKVT9771.avmta4-rme.xtra.co.nz@mta3-rme.xtra.co.nz> for ; Tue, 25 Oct 2005 16:31:17 +1300 Received: from bob2l2u6k2n1g3 ([222.153.247.182]) by mta3-rme.xtra.co.nz with SMTP id <20051025033117.VXEG3578.mta3-rme.xtra.co.nz@bob2l2u6k2n1g3> for ; Tue, 25 Oct 2005 16:31:17 +1300 Message-ID: <005d01c5d914$97679b10$e801a8c0@bob2l2u6k2n1g3> From: "Vernall" To: rsgb_lf_group@blacksheep.org References: <1811814855.20051024154952@sibru.ru> <000201c5d8e8$6574e8a0$5611f4cc@p1i5f0> <016a01c5d8e6$8baee5e0$54ecfea9@server> Date: Tue, 25 Oct 2005 16:29:10 +1300 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Subject: LF: Re: Toroid winding question Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit 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: by PlusNet MXCore (v2.00) Dear JB VE3EAR - VE3WZL, Leakage inductance increases with separation between primary and secondary, even if you had adjacent bobbins. I've done some frequency response tests on what I thought could be wideband transformers that had separated primary and secondary and the measured results were more narrowband than I thought they could be. I believe the reason is incomplete flux linkages as the ferrite core material is not the only magnetic path, even if it is the main one, and the "bypass flux" can be considered to contribute to leakage inductance. Wideband performance continues to need "transmission line" winding technique. For use in transmitter finals, leakage reactance stored energy can result in spikes. 73, Bob ZL2CA ----- Original Message ----- From: "J. B. Weazle McCreath" To: Sent: Tuesday, October 25, 2005 11:01 AM Subject: LF: Toroid winding question > Hello LFers, > > How critical is the spacing between the windings and the core material > when > winding a toroidal transformer? I have a core taken from a television > flyback > transformer that I'd like to experiment with using different winding > techniques. > To simplify things, I was thinking of putting the windings onto bobbins > that > could quickly be slipped on and off of the core. Would I be OK with using > a bobbin with 1/8 inch (3 mm) wall thickness or should I look for > something > with a thinner wall? Any and all comments welcome. > > 73, J.B., VE3EAR - VE3WZL > Solar and wind powered > EN93dr > > > >