# What is an Inductive Reactance : Definition, Unit and Formula

## What is Inductive Reactance?

### 归纳抗抵抗公式衍生

Inductive reactance is the term related to AC circuits. It opposes the flow of current in AC circuits. In an AC inductive circuit due to phase difference, the current waveform “LAGS” the applied voltage waveform by 90 degrees .i.e if the voltage waveform is at 0 degrees, the current waveform will be at -90 degrees.

In an Inductive circuit, the inductor is placed across the AC voltage supply. The self-induced emf in the inductor increases and decreases with the increase and decrease in the supply voltage’s frequency. Self-induced emf is directly proportional to the rate of change of current in the inductor coil. The highest rate of change occurs when the supply voltage waveform crosses over from the positive half cycle to a negative half cycle or vice-verse.

IL= I.最大限度. sin(ωt – 900) , φωis in radians and ‘t’ in seconds

### 例子

Let’s look at an example to calculate the inductive reactance.

An inductor with inductance 200mH and zero resistance is connected across a 150v voltage supply. The frequency of voltage supply is 60Hz. Calculate the inductive reactance and the current flowing through the inductor

XL=2πfl.

=2π×50×0.20

= 76.08欧姆

IL= V.L/ XL

= 150 / 76.08

= 1.97 A.