What is electrical impendance?

Impedance (Z) is the vector sum of a circuit's resistance (R) and reactance(X), is expressed in ohms, and is the total opposition to current in an a.c. circuit.

Resistance, expressed in ohms, depends upon the length, cross-sectional area, and resistivity of the conductor.

Reactance, expressed in ohms, can be inductive reactance (XL), capacitive reactance(XC), or a combination (vector sum) of the two.

• Inductive reactance is directly proportional to the circuit's inductance and the supply frequency.
• Capacitive reactance is inversely proportional to the circuit's capacitance and the supply frequency.