Capacitive Reactance Definition

In physics, capacitive reactance is defined as the opposition offered by a capacitor to change the potential difference or voltage across its plates. Capacitance values are typically measured in ohm (Ω) and represented by (Xc). Moreover, the value of capacitive reactance relies on how quickly a capacitor charges and releases electrons in electromagnetic fields. Or in other words, capacitive reactance is said to be inversely proportional to the capacitance and signal frequency.


Formula of Capacitive Reactance

To know how to calculate a capacitor's charge, you can use the formula listed below:

Xc = 1 / (2πfC)


C = Capacitance

f = Frequency

2π = 6.283


To calculate the capacitive reactance, you can use our Capacitive Reactance Calculator.


To get a better understanding of how capacitive reactance works, let's solve an example below:

Suppose if a circuit has a capacitor of 350nF, providing a current at the frequency of 15 kHz, then determine a capacitor's capacitive reactance value.

Given data

Capacitance = C = 350 nF = 350 × 10-9 F
Frequency = f = 15 kHz = 15 × 103 Hz

To Find

Capacitive reactance = ?


To find out the capacitive reactance of a capacitor, we will use the formula listed below:

Xc = 1 / (2πfC)

Putting values in the formula:

Xc = 1 / (6.283) × (15 × 103 Hz) × (350 × 10-9 F)
Xc = 30.31 Ω