Enter a Capacitance (C) and Frequency (f) — along with their respective units — into the Capacitive Reactance Calculator to find the Capacitive Reactance (XC), plus the Angular Frequency (ω) and Impedance Magnitude of your AC circuit.
Capacitive Reactance (XC)
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Angular Frequency (ω)
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Impedance Magnitude
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Capacitive reactance (XC) is the opposition that a capacitor offers to alternating current (AC) flow. It's measured in ohms (Ω) and decreases as frequency increases, which is opposite to inductive reactance.
Using the formula XC = 1/(2πfC), with C = 15 nF (15 × 10⁻⁹ F) and f = 60 Hz: XC = 1/(2π × 60 × 15 × 10⁻⁹) = 176,839 Ω or approximately 177 kΩ.
Capacitive reactance (XC) is measured in ohms (Ω), the same unit as electrical resistance. This is because reactance represents opposition to current flow, just like resistance.
Capacitive reactance is inversely proportional to frequency. As frequency increases, capacitive reactance decreases. At very high frequencies, a capacitor acts almost like a short circuit, while at DC (0 Hz), it acts like an open circuit.
Resistance opposes current flow in both AC and DC circuits and dissipates energy as heat. Reactance only opposes AC current flow and stores/releases energy without dissipating it. Both are measured in ohms.
In DC circuits, the frequency is zero (f = 0). Since XC = 1/(2πfC), when f = 0, the reactance becomes infinite, meaning no current flows through the capacitor in steady-state DC conditions.
In a circuit with resistance (R) and capacitive reactance (XC), the total impedance magnitude is Z = √(R² + XC²). The phase angle is θ = arctan(-XC/R), where the negative sign indicates the current leads the voltage.