In a DC circuit, there is no current through a capacitor -- or through this simple circuit that contains a capacitor.
In a simple resistor circuit, we defined resistance R by
V = I R
In a similar fashion, we can write
VC = I XC
where VC is the maximum voltage across the capacitor and I is the maximum current through the circuit. XC is called the "capacitive reactance"; it is analogous to resistance and is also measured in ohms (). The "capacitive reactance", XC, is given by
XC, the "Capacitive Reactance" plays a role very similar to that of R, the resistance. The capacitive reactance is a measure of how difficult it is for current to flow. With AC circuits, this depends upon the frequency.
(c) Doug Davis, 2002; all rights reserved
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