1. What is Capacitive Reactance?

Capacitive reactance (X_c) is the opposition that a capacitor presents to alternating current. Unlike resistance, reactance varies with frequency and is measured in ohms (Ω).

2. How Does the Calculator Work?

The calculator uses the capacitive reactance formula:

Where:

• \( X_c \) — Capacitive reactance (Ω)
• \( f \) — Frequency (Hz)
• \( C \) — Capacitance (Farads)
• \( \omega \) — Angular frequency (rad/s) = \( 2\pi f \)

Explanation: The reactance decreases with increasing frequency or capacitance. At DC (0 Hz), reactance is theoretically infinite (open circuit).

3. Importance of X_c Calculation

Details: Calculating capacitive reactance is essential for designing filters, timing circuits, AC coupling networks, and impedance matching in electronic circuits.

4. Using the Calculator

Tips: Enter frequency in radians per second (ω) or convert from Hz (ω = 2πf). Enter capacitance in Farads (1 μF = 0.000001 F). All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between resistance and reactance?
A: Resistance opposes both AC and DC equally, while reactance varies with frequency and only opposes AC current.

Q2: Why does reactance decrease with frequency?
A: At higher frequencies, the capacitor has less time to charge/discharge, effectively presenting less opposition to current flow.

Q3: What happens at DC (0 Hz)?
A: The reactance becomes infinite, meaning capacitors block DC current (after initial charging).

Q4: How does reactance affect phase?
A: In a pure capacitor, current leads voltage by 90 degrees due to the reactance.

Q5: What about real capacitors with ESR?
A: Real capacitors have equivalent series resistance (ESR) which adds to the total impedance, especially important at high frequencies.