Path: utzoo!attcan!uunet!cs.utexas.edu!uwm.edu!ux1.cso.uiuc.edu!midway!mimsy!mojo!disney!josip From: josip@ra.src.umd.edu (Josip Loncaric) Newsgroups: sci.electronics Subject: Re: A conundrum about the AWG (wire gauge) table Summary: wire gauge is -20*log10(circumference inches) Keywords: wire gauge Message-ID: <1990Sep13.181852.24683@ra.src.umd.edu> Date: 13 Sep 90 18:18:52 GMT References: <2588@ryn.esg.dec.com> <5170089@hplsla.HP.COM> <1990Sep13.173238.9156@canterbury.ac.nz> Sender: news@ra.src.umd.edu (The News System) Organization: Systems Research Center, University of Maryland, College Park Lines: 32 In article <1990Sep13.173238.9156@canterbury.ac.nz> elec140@canterbury.ac.nz writes: >In article <5170089@hplsla.HP.COM>, tomb@hplsla.HP.COM (Tom Bruhns) writes: >> jeffw@midas.WR.TEK.COM (Jeff Winslow) writes: >>>In article <5170088@hplsla.HP.COM> tomb@hplsla.HP.COM (Tom Bruhns) writes: >>>>Dunno how it all got started, but you should note that a change of >>>>3 in gauge number corresponds exactly to a 2:1 cross-section change. >> >>>Are you sure about that, Tom? According to the tables I have here, it's >>>about half a percent off. > >Just to add more fuel to the fire, if you use decibels (defined as 10log(x), >where the log is base 10 and the x is a ratio) then a ratio of 2 is 3.01dB. >Decibels are a common engineering unit (at least in Electrical Engineering), so >perhaps the gauges sizes are based on this. > I tried that... B&S wire gauge seems to be roughly equal to -20 * log10 (wire circumference in inches) or, alternatively, wire diameter in inches is just 1 / (pi * 10^(gauge/20)) which seems to fit my B&S wire gauge table reasonably well... I'll be very pleased if this is actually THE formula... -- Josip Loncaric / SRC / U. of Maryland / -------------------------------------------------------------- ! Today's Special: Opinions....$0.02 each ! --------------------------------------------------------------