The delay would be the same for each wire regardless of length as I understand
it (which very well could be wrong) , so the travel time as a ratio of length
is still accurate.
Jonas Payne
PBR
Cell: (702) 358-5084
-----Original Message-----
From: healeys-bounces@autox.team.net [mailto:healeys-bounces@autox.team.net]
On Behalf Of Alex
Sent: Thursday, May 31, 2012 1:46 PM
To: Richard Ewald; John Sims
Cc: Healey List
Subject: Re: [Healeys] ingnition leads
Actually, there is a slight error in these calculations. Every cable, wire,
circuit board conductor, waveguide, optical fibre, etc. offers a slight delay
to a propagating electrical signal traveling along the wire. This delay is
called the velocity factor.
Learn more here: http://en.wikipedia.org/wiki/Wave_propagation_speed
For example, in a coaxial cable, the VF is usually 0.66 or so, which means
when calculating length for an application based on the speed of light, you
assume the speed of light is reduced by about a third. Manufacturers of these
cables supply the VF as a spec.
Hee hee!
== Alex in Maine
"The Blue Mainie," 1960 Austin Healey 3000 BT7
"Conkling," 1946 M.G. TC #1321
Former owner 1957 A-H 100-6, 1967 A-H BJ8,
1965 MG Midget
http://home.roadrunner.com/~alexmm
----- Original Message -----
From: "Richard Ewald" <richard.ewald@gmail.com>
To: "John Sims" <ahbn6@verizon.net>
Cc: "Healey List" <Healeys@autox.team.net>
Sent: Thursday, May 31, 2012 2:43 PM
Subject: Re: [Healeys] ingnition leads
> Yes it is, but I didn't use a light year, I used the speed in miles per
> hour and converted to inches per second. From there is it trivial to see
> how long it takes to cover 1". :-)
> The time required to cover 2, 3 and 4 inches will be left as an exercise
> to
> the student.
> Rick
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