Previous in Forum: Electrical Earthing   Next in Forum: Voltage Level
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
8 comments
Rate Comments: Nested
kecman
Active Contributor

Join Date: Jan 2007
Location: Altadena, California, USA
Posts: 12

Capacitance Calculator for 2D Geometry

05/24/2012 7:11 AM

Does anyone know of a free or inexpensive software package for calculating capacitance in 2D geometry?

We cannot afford one of those CAD systems used in device modeling that could certainly do the job, but our goal is to calculate inter-contact capacitances of a thin, Al-plated, Si detector typically used in scientific cosmic-ray instruments. The surface of the detector is partitioned into several closely spaced regions, each connected to its contact on the perimeter of the detector. Often there is a tiny Al trace bringing the signal of a region "X" and running in between two other regions, "Y" and "Z". The inter-contact capacitances are very important in estimating the future cross-talk between the detector regions for the design purposes, i.e., before any detectors are made.

Sorry, not allowed to post any photos. Thanks!
Register to Reply
Pathfinder Tags: 2D capacitance
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Good Answers:

These comments received enough positive votes to make them "good answers".

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
3
redfred
Guru
Engineering Fields - Electrical Engineering - Been there, done that. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 15600
Good Answers: 981
#1

Re: Capacitance Calculator for 2D Geometry

05/24/2012 10:30 AM

Capacitors do not exist in two dimensions! Capacitance is determined by the overlapping area of two conductors separated by an insulator with a certain permittivity between the two conductors.

__________________
 "Don't disturb my circles." translation of Archimedes last words
Register to Reply Good Answer (Score 3)
No more Good Answers. Go to first "Almost" Good Answer
kecman
Active Contributor

Join Date: Jan 2007
Location: Altadena, California, USA
Posts: 12
#2
In reply to #1

Re: Capacitance Calculator for 2D Geometry

05/24/2012 2:42 PM

This is a little more exotic case of capacitance where the electric field lines between the adjacent co-planar detector segments close through both the air and silicon. Another example is a thin Al trace running next to a co-planar Al plate or between two co-planar Al plates. They all make a "2D" capacitor, and no matter how small its capacitance is, we would like to calculate it.

There is also the bulk capacitance of each detector segment in the classical sense of two parallel plates since the back side of the Si detector is Al-plated and serves as the common electrode for the partitioned segments of the front side. But that is a 3D geometry case, not of interest here.
Register to Reply
redfred
Guru
Engineering Fields - Electrical Engineering - Been there, done that. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 15600
Good Answers: 981
#3
In reply to #2

Re: Capacitance Calculator for 2D Geometry

05/24/2012 5:04 PM

There are no capacitors possible in Flatland.

Don't tell me that this is an exotic exception, either. I've worked on the designs and electronics for a Segmented Wire Ion Chamber (SWIC) and many other beam profile monitors where thin wires run parallel to many plates. This is done all the time in RF strip line designs to make directional couplers, too.

So do your homework, crack open that old textbook or hire a consultant. But don't wave the proprietary flag while asking for help in solving a fundamental Physics / Electrical Engineering problem. That is insulting.

__________________
 "Don't disturb my circles." translation of Archimedes last words
Register to Reply Score 1 for Good Answer
No more "Almost" Good Answers.
ci139
Guru

Join Date: Feb 2012
Posts: 595
#5
In reply to #3

Re: Capacitance Calculator for 2D Geometry

05/26/2012 11:05 AM

CR4 ADMIN: Deleted Post

Abuse/Attack: This post was deleted because it was an attack on another user. Please review the CR4 Site FAQ and the CR4 Rules of Conduct.

__________________
 ci139
Register to Reply Off Topic (Score 5)
ci139
Guru

Join Date: Feb 2012
Posts: 595
#6
In reply to #5

Re: Capacitance Calculator for 2D Geometry

05/26/2012 4:18 PM

i haven't needed net capacitance so i dont have these formulas

but i 've needed inductances so

http://www.hot.ee/rjc/files/CR4/Untitled-7old.jpg

http://www.hot.ee/rjc/files/CR4/Untitled-220new.jpg

µ(1)=1
µo(N/A²)=1.25664E-06
n(1)=100
l(m)=0.01
r(m)=0.003
d(=2r)=0.006
L.1stPass(H)=5.672E-05
L.2ndPass(H)=4.264E-05
L.from[http://www.qsl.net/in3otd/indcalc.html](H)=2.800E-05

i trust the least coz i don't trust myself (not fully into this subject)

you tell me witch is by the book & if any is correct ... in ... real

__________________
 ci139
Register to Reply
redfred
Guru
Engineering Fields - Electrical Engineering - Been there, done that. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 15600
Good Answers: 981
#7
In reply to #6

Re: Capacitance Calculator for 2D Geometry

05/26/2012 4:53 PM

That image is so large I cannot fit a page onto my laptop to tell what you are trying to do, let alone if you made an honest mistake somewhere.

__________________
 "Don't disturb my circles." translation of Archimedes last words
Register to Reply Off Topic (Score 6)
SolarEagle
Guru

Join Date: Mar 2007
Location: by the beach in Florida
Posts: 33392
Good Answers: 1817
#4

Re: Capacitance Calculator for 2D Geometry

05/24/2012 6:23 PM

http://m.iopscience.iop.org/0953-8984/21/2/025904
http://www-mech.eng.cam.ac.uk/profiles/fleck/papers/247.pdf

https://www.fieldp.com/order.html#toolkits

__________________
 All living things seek to control their own destiny....this is the purpose of life
Register to Reply
amnakhan1245
Active Contributor

Join Date: Jun 2012
Posts: 22
#8

Re: Capacitance Calculator for 2D Geometry

06/07/2012 1:53 PM

CR4 ADMIN: Deleted Post

Spam: This post was deleted because it contained advertising outside the Commercial Space forum. Please review Section 14 of the CR4 Site FAQ about advertising.
Register to Reply Off Topic (Score 5)
Register to Reply
Have a Different Question?
8 comments

Good Answers:

These comments received enough positive votes to make them "good answers".

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Copy to Clipboard

Users who posted comments:

amnakhan1245 (1); ci139 (2); kecman (1); redfred (3); SolarEagle (1)

Previous in Forum: Electrical Earthing   Next in Forum: Voltage Level

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Electrical Engineering:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (58 right now)
Show Members
Advertisement