What is the impedance angle of a capacitor?

What is the impedance angle of a capacitor?

• A. -90°
• B. 0°
• C. +90°
• D. 180°

Answer: (A)

The impedance angle of a capacitor is significant because it helps in understanding how capacitors behave in an AC circuit. A capacitor stores energy in an electric field, and when we analyze its impedance, we focus on how this energy storage affects the phase relationship between current and voltage. The impedance (Z) of a capacitor can be defined as Z = 1/jωC, where j is the imaginary unit, ω is the angular frequency, and C is the capacitance. When we express this in terms of magnitude and phase, the magnitude of the impedance is |Z| = 1/(ωC), which is a positive value, but the phase angle is -90°. This negative angle indicates that the current through the capacitor leads the voltage across it by 90 degrees. This phase difference is essential because it shows that when voltage reaches its peak (maximum positive value), the current is already decreasing toward zero. The impedance angle of -90° is particularly important in reactive power calculations and in understanding the power factor in AC circuits. A power factor of 1 (or unity) indicates that the load is purely resistive, whereas a capacitive load leads to a negative angle, showing that it is providing reactive power to the circuit. In

The impedance angle of a capacitor is significant because it helps in understanding how capacitors behave in an AC circuit. A capacitor stores energy in an electric field, and when we analyze its impedance, we focus on how this energy storage affects the phase relationship between current and voltage.

The impedance (Z) of a capacitor can be defined as Z = 1/jωC, where j is the imaginary unit, ω is the angular frequency, and C is the capacitance. When we express this in terms of magnitude and phase, the magnitude of the impedance is |Z| = 1/(ωC), which is a positive value, but the phase angle is -90°.

This negative angle indicates that the current through the capacitor leads the voltage across it by 90 degrees. This phase difference is essential because it shows that when voltage reaches its peak (maximum positive value), the current is already decreasing toward zero.

The impedance angle of -90° is particularly important in reactive power calculations and in understanding the power factor in AC circuits. A power factor of 1 (or unity) indicates that the load is purely resistive, whereas a capacitive load leads to a negative angle, showing that it is providing reactive power to the circuit.

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