Difference between revisions of "Impedance"
(First draft of impedance page.) 
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Revision as of 17:34, 25 April 2008
Impedance is a property of electrical circuits that "impedes" current from flowing. Fundamentally, there are two types of impedance: Resistance and Reactance.
The magnitude of impedance (represented by <math>Z\,</math>) of a circuit or component can be computed by taking the sum of the squares of the resistance (represented by <math>R\,</math>) and reactance (represented by <math>X\,</math>).
<math>Z = \sqrt{R^2 + X^2}\,</math>
However, it is more useful to represent impedance as a complex number and use it in phasor analysis.
Impedance can be used in the normal Ohm's Law equation:
<math>V = IZ\,</math>
where V is voltage and I is current. For working with alternating current, this is more correct than the usual direct current equation <math>V = IR\,</math>.