Question

What does Z stand for in AC circuit?

Answer 1

In an AC (alternating current) circuit, Z stands for impedance. Impedance is a measure of how much a component or a combination of components resists the flow of alternating current (AC). It's similar to resistance in a DC circuit, but impedance takes into account both resistance (R) and reactance (X).

1. Resistance (R) is the opposition to current flow in purely resistive elements, like resistors.
   

1. Reactance (X) is the opposition to current flow due to inductors and capacitors. It changes with the frequency of the AC signal.
   

Impedance is represented as a complex number:
\[ Z = R + jX \]
where:

1. \( R \) is the resistance (real part),
   

1. \( X \) is the reactance (imaginary part),
   

1. \( j \) is the imaginary unit (equivalent to the square root of -1).
   

So, impedance combines both the resistance and the reactance to give the total opposition to AC current, and it is measured in ohms (Ω).