Re: [femm] [Does injecting current change the indutanc and resistance values ?]

[dcm3c@xxxxxxx]

In a message dated 11/18/01 3:25:40 AM Eastern Standard Time, sxy28@xxxxxxxxxxx writes:


> (ps) When I put the +1A for two traces and -1A for ground, the total current 
> in the traces are not +1A (becoming less than +1A) as frequency increases 
> with the set-up above. When I inject the current +1A throughout the traces 
> and -1A for for ground by circuit property (without splitting conductor 3 
> pieces), it always turns out +1A and -1A regardless of freqeuncy.


When you set Source current density via a material property, this is the current that would be there at 0 Hz.  At nonzero frequencies, inductive impedance lowers the actual currents in the conductor.  By setting the source current density, you are really, in a sense, setting a constant (voltage gradient)*conductivity for the section that is independent of frequency.

When you set current to a particular value via a circuit property, the program solves an extra equation for what the applied voltage gradient that forces the current to be as specified.  Voltage gradient is whatever it needs to be to hold the current constant.

Dave.
--
David Meeker
http://members.aol.com/_ht_a/dcm3c