capacitors
capacitors
(OP)
Back in the early 60's I had course in the fundamentals of electricity. I remembered my instructor told the class that there was no current flow thru capacitors. I am bringing this subject now because the question recently surfaced and thru my infinite winsdom I restated what my instructor said about 35 years ago. However reading recent material I think that I may have stuck my foot in my mouth. I would appreciate some comments from the experts.






RE: capacitors
Namely, current I in amperes is:
I=jx2xPIxfxCxV
where:
PI is 3.14
f is frequency, e.g. 60Hz
C is capacitance in Farads
V is voltage in volts
RE: capacitors
Mike
RE: capacitors
1. IEEE Std 100 "Dictionary"
Displacement current is the time rate of change of the electric flux density.
Visit
http://rd11.web.cern.ch/RD11/rkb/PH14pp/node108.html
for Maxwell's equations
RE: capacitors
Michael Sidiropoulos
RE: capacitors
The intent is to make the dielectric non-conductive, so there is, by design, no DC current path. There are leaky capacitors, whose dielectrics are no longer working properly, and hence somewhat conductive
TTFN
RE: capacitors
--(|)--
You can't get any one-directional flow through such a device -- at least, not indefinitely, although a small "charging current" would flow for a short time while the rubber stretched out, and it would tend to help maintain a constant pressure (like a water tower, which is also providing "capacitance" to the system).
But an oscillating water pressure would be transmitted through this "water capactor", nearly unaffected.
Electrical capacitors work almost identically to the analogy outlined above.
A better model would perhaps incorporate a small hole in the membrane, which would represent a leakage resistance.
RE: capacitors
I AGREE THERE IS NO ACTUAL FLOW OF CURRENT WITH DC ELECTRICAL SYSTEM. W/ AN AC SYSTEM THERE IS AN AC FLOW WHICH IN A SENSE IS INTERRUPTED BY THE PLATES OF THE CAPACITOR ,HOWEVER THAT INTERRUPTION IS STORED IN BOTH PLATES VIA A MAGNETIC FIELD BETWEEN THEM. THAT AC MAGNETIC FIELD POLARITY REVERSES, MAKING ALTERNATING CURRENT APPEAR TO FLOW THRU THE CAPACITOR BUT IN ACTUALLITY IS NOT. DO IO HAVE RIGHT? NEED MORE INPUT FROM PARTICIPANTS. THKS!!
RE: capacitors
RE: capacitors