AC Circuit Analysis


Impedance, represented by the symbol , is a measure of the opposition to electrical flow. It is measured in ohms .


Difference between Resistance and Impedance?

Resistance is measured for DC circuits. Impedance is a more complex concept that includes resistance, but also the Reactance.

Khan Academy

I saw this Khan academy video where they use this formula, which is the norm of Impedance.

In general, for , , and combinations, the impedance is defined to be the ratio between the Voltage Phasor and the Current Phasor .

Impedance of Resistance

Impedance of Inductance

Impedance of Capacitance

Rectangular Form

Another definition of Impedance is simply combining resistance and Reactance (which is defined for both and )

Combinations of Impedance

These follow the same formula as for Resistor, but they are in terms of complex impedances instead of real resistance.

For series impedances, the formula is

For parallel impedances, the formula is