Question

Impedance, in general, is the opposition to voltage. (True/False)

Hint:

Always remember: $$\text{Resistance (DC)} = \text{Opposition to Current.}$$ $$\text{Impedance (AC)} = \text{Opposition to Current (combining Resistance and Reactance).}$$

Answer 1

Step 1: Defining Electrical Impedance ($Z$):
In AC circuit theory, electrical impedance ($Z$) is the total opposition that a circuit offers to the flow of alternating current (AC). It is measured in Ohms ($\Omega$).

Step 2: Analyzing the Mathematical Relationship:
Impedance is mathematically defined by Ohm's Law in AC circuits: $$Z = \frac{V}{I}$$ Where $V$ is the AC voltage across the circuit and $I$ is the AC current flowing through it. Impedance combines two distinct components:

• Resistance ($R$): Purely resistive opposition (independent of frequency).
• Reactance ($X$): Frequency-dependent opposition from inductors ($X_L = 2\pi f L$) and capacitors ($X_C = \frac{1}{2\pi f C}$).

Step 3: Conclusion:
Since impedance is the opposition to the flow of current ($I$) under an applied voltage ($V$), and not the opposition to voltage itself, the statement is False.