How is capacitor reactance affected by frequency?

How is capacitor reactance affected by frequency?

• A. It increases with increasing frequency
• B. It decreases with increasing frequency
• C. It remains constant at all frequencies
• D. It is irrelevant to frequency changes

Answer: (B)

Capacitor reactance is inversely related to frequency. This means that as the frequency of the alternating current (AC) increases, the reactance offered by the capacitor decreases. The formula for capacitor reactance is given by: \[ X_C = \frac{1}{2 \pi f C} \] where \(X_C\) is the capacitive reactance, \(f\) is the frequency, and \(C\) is the capacitance. From this formula, you can see that as frequency \(f\) increases, the overall value of \(X_C\) (the capacitance reactance) becomes smaller, leading to decreased reactance. In practical terms, this behavior is important in AC circuits because it means that higher frequencies lead to lower opposition to current flow in capacitive components. This relationship is crucial for understanding how capacitors behave in various applications, such as filters, timing circuits, and power factor correction. Choices suggesting that reactance increases, remains constant, or is irrelevant to frequency changes do not align with the fundamental principles of how capacitors operate in AC circuits. The behavior described by the correct answer is essential for effectively using capacitors in HVAC and other electrical systems.

Capacitor reactance is inversely related to frequency. This means that as the frequency of the alternating current (AC) increases, the reactance offered by the capacitor decreases.

The formula for capacitor reactance is given by:

[

X_C = \frac{1}{2 \pi f C}

]

where (X_C) is the capacitive reactance, (f) is the frequency, and (C) is the capacitance. From this formula, you can see that as frequency (f) increases, the overall value of (X_C) (the capacitance reactance) becomes smaller, leading to decreased reactance.

In practical terms, this behavior is important in AC circuits because it means that higher frequencies lead to lower opposition to current flow in capacitive components. This relationship is crucial for understanding how capacitors behave in various applications, such as filters, timing circuits, and power factor correction.

Choices suggesting that reactance increases, remains constant, or is irrelevant to frequency changes do not align with the fundamental principles of how capacitors operate in AC circuits. The behavior described by the correct answer is essential for effectively using capacitors in HVAC and other electrical systems.