Calculate the capacitive reactance of a capacitor at any frequency. Enter frequency and capacitance to calculate XC using the standard formula XC = 1/(2πfC). Results are provided in ohms.
Enter the operating frequency and capacitor value to calculate capacitive reactance.
XC = capacitive reactance
f = frequency in Hz
C = capacitance in farads
Capacitive reactance is calculated from the reciprocal of the product of angular frequency and capacitance.
For a fixed capacitor, increasing frequency decreases capacitive reactance. This makes capacitors increasingly effective at passing higher-frequency AC signals.
For a fixed frequency, increasing capacitance decreases capacitive reactance.
The calculator automatically converts your selected frequency and capacitance units into SI units before applying the reactance formula.
Enter the operating frequency in Hz, kHz, MHz, or GHz.
Enter the capacitor value in pF, nF, µF, mF, or F.
The calculator applies Xc = 1/(2πfC) and displays the result in ohms.
Consider a 100 nF capacitor operating at a frequency of 1 kHz.
| Quantity | Value |
|---|---|
| Frequency | 1,000 Hz |
| Capacitance | 100 nF |
| Capacitance in farads | 0.0000001 F |
| Formula | Xc = 1 / (2πfC) |
| Reactance | ≈ 1,592 Ω |
Therefore, a 100 nF capacitor has approximately 1.59 kΩ of capacitive reactance at 1 kHz.
Calculate the reactance of capacitors used in high-pass, low-pass, and other filter circuits.
Determine how strongly a capacitor opposes AC current at a particular frequency.
Use capacitive reactance when analyzing the impedance of AC and RLC circuits.
Estimate capacitor reactance when selecting coupling and bypass capacitors.
Unlike a resistor's resistance, a capacitor's opposition to AC changes with frequency. At higher frequencies, XC becomes smaller. At lower frequencies, XC becomes larger. This frequency-dependent behavior is one of the main reasons capacitors are widely used in filters, coupling networks, timing circuits, and signal conditioning.
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Capacitive reactance is the opposition a capacitor presents to alternating current. It is measured in ohms and is represented by Xc.
The standard formula is Xc = 1/(2πfC), where Xc is capacitive reactance in ohms, f is frequency in hertz, and C is capacitance in farads.
Capacitive reactance decreases as frequency increases. The relationship is inversely proportional, so a higher frequency produces a lower Xc for the same capacitor.
Capacitive reactance decreases when capacitance increases. A larger capacitance provides lower opposition to AC at the same frequency.
For an ideal capacitor at zero frequency (DC), capacitive reactance approaches infinity. After a transient, an ideal capacitor behaves as an open circuit to steady-state DC.
Frequency should be expressed in hertz and capacitance in farads. The resulting capacitive reactance is expressed in ohms.