Return-Path: Received: (qmail 1344 invoked from network); 23 May 2001 14:29:05 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 23 May 2001 14:29:05 -0000 Received: (qmail 29158 invoked from network); 23 May 2001 14:28:30 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 23 May 2001 14:28:30 -0000 Content-Transfer-Encoding: 8bit Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 152ZWo-0006Wj-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 23 May 2001 15:22:22 +0100 X-Priority: 3 Received: from bob.dera.gov.uk ([192.5.29.90]) by post.thorcom.com with esmtp (Exim 3.16 #2) id 152ZWl-0006We-00 for rsgb_lf_group@blacksheep.org; Wed, 23 May 2001 15:22:19 +0100 X-MSMail-Priority: Normal Received: by bob.dera.gov.uk; (8.8.8/1.3/10May95) id PAA03852; Wed, 23 May 2001 15:26:03 +0100 (BST) Received: (qmail 5113 invoked from network); 23 May 2001 15:15:56 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from gauntlet.mail.dera.gov.uk (172.16.9.10) by baton.dera.gov.uk with SMTP; 23 May 2001 15:15:56 -0000 Received: by gauntlet.mail.dera.gov.uk; id PAA24098; Wed, 23 May 2001 15:09:17 GMT Received: from unknown(10.71.64.31) by gauntlet.mail.dera.gov.uk via smap (3.2) id xma023300; Wed, 23 May 01 15:07:19 GMT Received: from FRN-MAIL-R1.dstl.gov.uk (unverified) by mailguard.dera.gov.uk (Content Technologies SMTPRS 4.1.5) with ESMTP id for ; Wed, 23 May 2001 15:27:58 +0100 Received: by frn-mail-r1.dstl.gov.uk with Internet Mail Service (5.5.2650.21) id ; Wed, 23 May 2001 15:19:43 +0100 Message-ID: <7D653C9C42F5D411A27C00508BF8803D55C491@pdw-mail-r1.dstl.gov.uk> From: "Talbot Andrew" To: rsgb_lf_group@blacksheep.org Subject: LF: RE: Big PA Date: Wed, 23 May 2001 15:19:36 +0100 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset=iso-8859-1; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: > Could you give me info on the little pot-core you use for your driver > transformer in your PA? Material, turns? > > I used a Farnell 559-570 ferrite sleeve, intended for EMC suppression, > no info on material, 16 turns on primary (1.1 mH) and 29 turns It is a pot core, RM10 size and must be ungapped and needs to be this big to get all the insulated turns on, although for power requirements alone, a much smaller core will do. The core is otherwise OK for 50 Watt SMPSUs. Material 3C85 or similar for SMPSU use. 12 turns on all windings, ie 3 x 12 in total - two windings for the FETs and one input. 1:1 turns ratio is ideal, as the FETS are then switched with a +/- 15 V drive signal, assuming the TC4426 is run from a 15V rail. The TC4426 gives out a 0 - 15V waveform so directly coupling into a transformer.......... I guess it only survived at all coz of some sort of protection built in ! Also, ferrite material designed for EMC use is designed to be lossy - this sort of sleve / core should never really be used for anything other than suppression. I can supply an 81K size .PCX file of the full circuit diagram. If anyone wants a copy please contact me directly as it is too big to send on the reflector. Does anyone want to host it on their web page ? In view of the EMail problems on this account earlier, can you also copy requests to g4jnt@thersgb.net just in case this packs up again. Andy G4JNT -- The Information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful.