[sci.electronics] inductance calculations

phil@brahms.amd.com (Phil Ngai) (05/11/91)

I know that with generous doses of calculus and Maxwell's equations the
inductance of a particular geometry can be derived from first
principles, but being a lazy person, I was wondering if there are any
books with the formulas already derived. Particular emphasis on the
type of geometries found on printed circuit boards.

--
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tk@wheat-chex.ai.mit.edu (Tom Knight) (05/12/91)

You might look at "Radio Instruments and Measurements", PB-264 261,
published by the National Bureau of Standards, Jan. 1937.  It's
available from NTIS.  They include calculation of flat spiral inductance,
which presumably is what your are most interested in.

There is also a book "Inductance Calculations" reprinted by the
Instrument Society of America.  I forget the author at the moment; my
copy is at home.

If you have specific questions, I'd be glad to help.

ornitz@kodak.kodak.com (Barry Ornitz) (05/14/91)

In article <1991May10.170055.1336@amd.com> phil@brahms.amd.com 
(Phil Ngai) writes:
>I know that with generous doses of calculus and Maxwell's equations the
>inductance of a particular geometry can be derived from first
>principles, but being a lazy person, I was wondering if there are any
>books with the formulas already derived. Particular emphasis on the
>type of geometries found on printed circuit boards.

Try "Inductance Calculations" by Frederick W. Grover.  It was originally
published in 1946 by Van Nostrand.  It is now reprinted by permission of Dover
Publications by the Instrument Society of America.  It's ISBN number is
0-87664-557-0.  The ISA can be reached at P. O. Box 12277, Research Triangle
Park, NC  27709.

This book is available by the ISA because of the constant need to determine
inductance values of intrinsically safe instrumentation. [Inductance and
capacitance are energy storage elements, of course.]

This book covers an extremely broad number of situations.
					Barry

 -----------------
|  ___  ________  |       Dr. Barry L. Ornitz          WA4VZQ
| |  / /        | |       Eastman Kodak Company
| | / /         | |       Eastman Chemical Company Research Laboratories
| |< < K O D A K| |       Process Instrumentation Research Laboratory
| | \ \         | |       P. O. Box 1972, Building 167B
| |__\ \________| |       Kingsport, TN  37662       615/229-4904
|                 |       INTERNET:   ornitz@kodak.com
 -----------------

phil@brahms.amd.com (Phil Ngai) (05/22/91)

In article <15807@life.ai.mit.edu> tk@wheat-chex.ai.mit.edu (Tom Knight) writes:
|You might look at "Radio Instruments and Measurements", PB-264 261,
|published by the National Bureau of Standards, Jan. 1937.  It's
|available from NTIS.  They include calculation of flat spiral inductance,
|which presumably is what your are most interested in.
|
|There is also a book "Inductance Calculations" reprinted by the
|Instrument Society of America.  I forget the author at the moment; my
|copy is at home.

Thanks Tom, your reply was quite helpful. Although I guess you are
talking about people who want to make inductors on PCBs, while I am
more interested in calculating parasitic, unavoidable inductance.

I have ordered I.C. In the mean time, I found a table in a handbook
in the public library.

I also got the following suggestions. Thanks to Steve, Paul, Barry,
and Wolfgang.

*****************************************************************************
Using transmission-line techniques for PCB design seems to be getting
called "stripline" technology these days.  That's a good keyword to
use for getting into the literature, I suspect.

Any good E&M text will have the derivation for coax and wire-over-plane
configurations.  One or the other should be close enough for most PCB
situations.

*****************************************************************************
Should be plenty - look for references about stripline techniques (e.g.,
microwave parts made out of PCB traces).  Depending upon what kind of
precision you require, there are several "rules of thumb" which people
use - like a 0.10" trace over a ground plane on a "normal" PCB looks like
a 50-ohm transmission line.  And most "normal" size wires (and traces)
have an inductance of about NNN nF/inch (I forget the number tho).  Good
luck - I expect you'll receive some interesting replies.

*****************************************************************************
Try "Inductance Calculations" by Frederick W. Grover.  It was originally
published in 1946 by Van Nostrand.  It is now reprinted by permission of Dover
Publications by the Instrument Society of America.  It's ISBN number is
0-87664-557-0.  The ISA can be reached at P. O. Box 12277, Research Triangle
Park, NC  27709.

This book is available by the ISA because of the constant need to determine
inductance values of intrinsically safe instrumentation. [Inductance and
capacitance are energy storage elements, of course.]

This book covers an extremely broad number of situations.
*****************************************************************************
<one of my E&M texts points out that for voltages and currents commonly
achieved in the lab, inductors can store around 100 times as much energy
as capacitors.>

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Conflict of interest?