**Impedance (Z)** is similar to **Resistance (R)** . Impedance and Resistance both oppose the current in circuit. Both are almost the same thing , But **resistance related to** **DC Circuit**. Resistance oppose the steady electric current in DC circuit. **Resistance** **remains same** (constant) at any different frequency range.

**Impedance is related with AC circuit**. Impedance **vary** accordting to changing the frequency, this is not constant at different frequency range. Impedance also includes reactance (Inductive and capacitive property of the circuit).

**Reactance- **Reactance is the Resistance produced to AC Currents by Inductors and Capacitors only. This is a measure of the type of opposition to AC electricity due to capacitance or inductance.

The **impedance** is denoted by **Z **and unit of it is **Ohm (Ω). **

If the level of ohm is higher then level impedance is also higher.

**Impedance = Resistance + Reactance (Either inductive or Capacitive or both)**

In DC circuit, **Impedance** is effective Resistance of the circuit.

** Z= R**

In AC circuits, it possesses both magnitude and phase, unlike resistance, which has only magnitude.

In the case of capacitor, When the frequency increased then the resistance (Impedance ) of capacitor decreases. In Inductor this is just opposite, When we increase the frequency range then Impedance increase in inductor.

**Impedance ****
**

**Impedance is defined as combination of resistance and reactance.**

As we cannot assume any circuit with DC Current without Resistance , We cannot assume a circuit with AC current without Impedance.

Rsistive Power- Energy burns by resistive power to Heat goes through that system ,

In Reactive Power- the energy goes to Antennas, Speaker, transmission line, cable etc represents how much energy to be stored and propagates. Not burn to heat ie Impedance.

**Resistance** ** **If there is Only **Resistor** is connected with Load in any circuit then is called Resistor.

** • Reactance** ** **** **If any circuit there is Only **inductor** or **capacitor** connected with load. Then the value of v/I is called reactance.

__In Reactance There are 2 cases__

**(1) **If **inductor** in conneted then in this case **recatance** is called **inductive** **reactence**,

and its value in scaler form X_{L} = ѡL, and in vector form X_{L}=JѡL Where ѡ=2Πf. Here If frequency is increased then the value of wL is also increased.

**(2)** If **Capacitor** is connected then the Reactance is called **Capacitive Reactance** and it is denoted by (scaler form) Xc =** **

In vector form ** ** Where ** **** **If frequency (f) is increased then value of Xc is decreased. ie **ω** inversly proportional to **2Πf**.

**♦ Impedance – ****If Any ircuit consist Resistance –Inductor. Or Resistance – Capacitor, Or Resistance-inducter-Capacitor. Then the value of v/I is called Impedance.**

It is denoted by ** **

**If Resistor(R) and Inductor(L)****connected –****The value of Impedance (scaler form)**

**In vector form Z= R+jωL **

**If Resistor (R) and Capacitor(C)****connected – Then**

**Impedance **** **

**And In vector form ipedance **

**If Resistor (R) , Inductor (L) capacitor (C) Connected****– Then**

**Impedance **** **

**In vector form **** **

**Phasor Diagram of Impedance**

__Unit__

**Impedance****– Ω****Reactance****– Ω****Resistance****– Ω**

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**Also Read What is NOT Gate Logic **

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