Return-Path: Received: (qmail 8435 invoked from network); 8 Apr 2002 06:56:45 -0000 Content-Transfer-Encoding: 8bit Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 8 Apr 2002 06:56:45 -0000 X-MSMail-Priority: Normal Received: (qmail 14202 invoked from network); 8 Apr 2002 06:56:44 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 8 Apr 2002 06:56:44 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16uUVY-0003Yx-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 08 Apr 2002 09:28:12 +0100 Received: from tlvsca.vim.tlt.alcatel.it ([194.243.74.245]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16uUVX-0003Ys-00 for rsgb_lf_group@blacksheep.org; Mon, 08 Apr 2002 09:28:11 +0100 Received: from tlvk7v (localhost [127.0.0.1]) by tlvsca.vim.tlt.alcatel.it (8.11.6/8.11.6) with SMTP id g386l0102444 for ; Mon, 8 Apr 2002 08:47:01 +0200 (MET DST) Date: Mon, 8 Apr 2002 08:25:25 +0100 From: "Claudio Girardi" Subject: Re: LF: still more loop inductance formulas To: rsgb_lf_group@blacksheep.org X-Mailer: Z-Mail Pro 6.2, NetManage Inc. [ZM62_16H] X-Priority: 3 Message-ID: MIME-Version: 1.0 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: Hello to everybody, regarding the loops inductance, Terman Radio Engineers' Handbook has formulas for single turn loops of many different shapes and also notes that these formulas have all the same general form; it references two articles in the Proceedings of the I.R.E. of 1927 and 1936, that should contain the formulas derivation, maybe I could be able to find one of them... It gives also a formula for the inductance of a single turn rectangle: said a and b the rectangle sides length, d the wire diameter, g the diagonal of the loop (g = a^2+b^2) (all in meters) the inductance is: L = 0.4*((a+b)*ln(4.0*a*b/d) - a*ln(a+g) - b*ln(b+g)) + 0.4*(2*g+d-2*(a+b)); Rik first formula agrees well with the one from Terman, at least for side ratios up to the stated limit of six, where the error is around 10% depending on the wire diameter. I performed some comparison of that formula with the one from Terman and with computer simulations, you can find some results on http://www.qsl.net/in3otd/rlsim.html I have also put on my site some forms for the inductance calculation of single turn loops of regular polygonal shape and of rectangular shape, they are at http://www.qsl.net/in3otd/ind1calc.html and http://www.qsl.net/in3otd/ind2calc.html I have seen the new Rik formula just this morning, hope to have the time soon to compare also that with the inductance simulations made... 73 de Claudio, IN3OTD