Chapter 18 in the 5th edition pages 18.12 and 18.13: Wiring demand Wd = Wc x å (in cm/cm² or in/in²) Wd = wiring demand; Wc = wiring capacity; å = PCB Layout efficiency *************************************** Wire capacity Wc = T x L/G (in cm/cm² or in/in²) T = number of traces per wiring channel or distance between two via pads L = number of signal layers G = wiring channel width or length between centers f via pads in T What's the third one? Bob Wilson E/M Designer, CID+ SpectraSensors, Inc. 11027 Arrow Route Rancho Cucamonga, CA 91730 (909) 948-4110 www.spectrasensors.com www.ipc.org -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of McGlaughlin, Jeffrey A Sent: Thursday, January 15, 2009 8:42 AM To: [log in to unmask] Subject: [TN] Wiring Density Calculations Can someone please send me copies of the 3 calculations for wiring density/wiring demand from Mr. Coomb's PCB Handbook (chapter 19 of 6th Ed.) My copy is not available (has gone missing with an intern) at present . TIA, Jeffrey A McGlaughlin, CID Engineering Designer Battelle 505 King Ave Columbus Ohio 43201-2693 Phone (614)424-7582 --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------