1. The current "through" a capacitor is the displacement current. It
does not consist of charge passing through the capacitor, but since
charge increases on one side and decreases on the other side, it will
seem as if current is passing through. Note that this is s transient
behaviour (the d/dt in Maxwell's curl(B) = u0 J + e0 u0 dE/dt equation).
In steady state, there is no current through the capacitor. An
alternating current flows "through" a capacitor because it is always
transient.

2. Thus when you measure a current "through" a capacitor, you measure
the charging, i.e. the current equals the charge accumulated per unit
time.

3. Personally, I like Bleaney & Bleaney's "Electricity and Magnetism",
but I know several people who would challenge that recommendation :-)
But any book on electromagnetic theory should do.

See also Isaac Wing Tak Chan's answer.

Martin Manscher

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of allwyn allwyn
> Sent: 15. oktober 2004 15:27
> To: [email protected]
> Subject: [mems-talk] Capacitance modelling
>
> Dear members,
> I am modelling a fluidic systems by means of simulating it as an
> equivalent electrical circuit. I have a few doubts and please help me
> in solving it
>
> I am modelling a fluidic capacitance which consists of a membrane
> deflected by means of pressure diffrence. hence there is no fluid flow
> across the membrane.here I have some doubts.
>
> 1. In electrical capacitance , is there is a flow of charge through
> the capacitor.
>    because physically the capacitance has a dielectric or an insulator
> which cannot pass charges in it.
>
> 2. so when I am measuring current across the capacitor what exactly I
> am measuring ? . Is it the charge difference between the two plates.
>
> 3. where can I learn more about capacitance. because as an electrical
> engineer I always think about alternating current flowing through the
> capacitor
>
> Thank you
>
> Allwyn
> _______________________________________________
> [email protected] mailing list: to unsubscribe or change your list
> options, visit
> http://mail.mems-exchange.org/mailman/listinfo/mems-talk
> Hosted by the MEMS Exchange, providers of MEMS processing services.
> Visit us at http://www.memsnet.org/
>