**Capacitive Reactance Formula**

**Capacitive reactance** ( X_{C}) is a measure of a **capacitor’s** opposition to alternating current. It is measured in ohms like resistance but **reactance** is more complex than resistance because its value depends on frequency (f) of the electrical signal passing through the **capacitor**.

A Capacitor is a current storing device. In electrical and electronic systems, reactance is all about the opposition of a circuit element to changes in current or voltage due to that element’s capacitance.

When the capacitor is connected to a DC supply voltage, it becomes charged to the value of the applied voltage, acts as a temporary storage device and maintains this charge as long as the supply voltage is present.

Capacitive Reactance Formula is expressed by

Where in,

L = inductance of the circuit,

C = capacitance and

f = frequency of ac mains

**Example 1**

Calculate the capacitive reactance if 40 mF is connected to a frequency generator of 50 Hz signal.

**Solution**

According to given parameters

F= 30 x 10^{-3}

C = 50Hz

The capacitance reactance formula is given by

Xc = 1 / 2πfC

= 1 / 2π×40×10^{−3}×50

= 0.106 Ω

**Example**

Calculate the reactance of capacitance in an AC circuit wherein the input signal has a frequency of 100 Hz and a capacitor has a capacitance of 1000mF in a circuit.

**Solution**

Given

Frequency f is 100 Hz

Capacitance C is 1000 mF

The capacitance reactance formula is given by

xc = 1 / 2πfc

xc = 1 / 2 π x 200 x 1000 x 10^{-3}

= 7.961 Ω

Hence, the capacitive reactance is 7.961 Ω