Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Question about capacity calculation in two spheres example.
Posted 17 mag 2019, 09:40 GMT-4 Electromagnetics, Low-Frequency Electromagnetics 0 Replies
Please login with a confirmed email address before reporting spam
There is great example in Comsol blog: "How to Calculate a Capacitance Matrix in COMSOL Multiphysics" (https://www.comsol.com/blogs/how-to-calculate-a-capacitance-matrix-in-comsol-multiphysics/).
All seems ok beside one point, i will be very thankful if someone can make it clear.
The question is: – According to equation for total charge of 1st conductor (Q1 = Cm11V1 + Cm12(V1 – V2) + ...), if we remove all conductors from the model beside 1st one, we obtain simple equation for capacity of single conductor Q1 = Cm11*V1.
– Consequently self-capacity of the first sphere Cm11 should be equal capacity of isolated sphere, that according to C = 4piEps0*r equals 11.3pF. But in example it equals 5.4pF (form mutual matrix calculation).
– Can someone tell please what the reason of this difference? Why Cm11 don’t equals capacity of single (isolated) sphere? Is there а something I am misunderstood?
Thanks for response.
Hello Gleb Kuman
Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.
If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.