## Impedance Formula and Theory

When we talk about AC circuit the term Impedance comes. Impedance is a very known term to us. Today we are going to know Impedance Formula and Theory with the explanation. In AC circuits impedance always present.

### Understanding What is Impedance practically:

To better understand the Impedance we should know about Inductive Reactance and Capacitive Reactance.
We know that resistor has the property of opposition to the flow of current. But how inductor and capacitor oppose the flow of current? let's know.

### Inductive Reactance:

The property of an inductor by virtue of which it offered opposition only to the flow of alternating current is called Inductive Reactance.

Remember that inductive reactance only exists in the AC circuit, not in DC.
Actually, each Inductor has a property of opposition to the flow of current (AC & DC both) according to their material property, this is called resistance. But inductance reactance property only exists when the AC apply to it.
So we can say the capacity of an Inductor to oppose the flow of current in AC circuit is greater than the DC circuit.

### Capacitive Reactance:

The concept of capacitive reactance is same as inductive reactance.
The property of a capacitor by virtue of which it offered opposition only to the flow of alternating current is called Capacitive Reactance.
Capacitive reactance also does not exist in DC circuit.

### Reactance:

If an AC series circuit containing only Inductor and capacitor do not contain Resistor, then the opposition offered by the combination of inductor and capacitor to the flow of alternating current is called Reactance(X).

#### Impedance:

A series AC circuit which containing Resistor, Inductor, and Capacitor. Now the opposition offered by the combination of Resistor, Inductor, and Capacitor to the flow of AC current which flows through it is called Impedance.

Now let's go the Impedance Formula.

### Impedance Formula:

The basic impedance formula is,

As the resistance=R, and the reactance=X
so the angle between voltage and current of the circuit will be,

For a purely resistive circuit, the impedance will be, Z=R
For a purely Inductive circuit, the impedance will be, Z= XL
For a purely Capacitive circuit, the impedance will be, Z= XC

For the R-L circuit,

The  reactance=inductive reactance
so the impedance formula will be,

For the R-C circuit,

The reactance=capacitive reactance
so the impedance formula will be,

For the R-L-C circuit,
if XL>XC

impedance,

If XL<XC
impedance,

If XL=XC
The impedance, Z=R

The impedance formula in complex form,