# Why an Inductor acts as a Short Circuit in DC Supply?

Table of content

• 4:1 min

• 28 Aug 2024

## What is the Role of Inductor in DC Circuit?

In short, there is no frequency in DC supply i.e. frequency in DC = 0.

We know that inductive reactance:

XL = 2πfL

If we put frequency as zero then inductive reactance of the inductance would be zero.

XL = 2 x 3.1415 x 0 x L … ( L = Inductance i.e. Value of Inductor)

XL = 0Ω.

This is the reason why inductive reactance is zero in DC power supply.

OK with theory but what is the exact reason behind the scene in real scenario and what if we connect an inductor to the DC source?

## What is the Effect of DC Supply on Inductor?

An inductor which is a passive device acts as a short circuit when DC applied across it. Actually, inductor stores energy in the form of magnetic field and restores back to the circuit when needed.

When DC applied across an inductor, the sudden changes of current produces self inducted EMF in it which opposes it producing cause i.e. change in the current (Len’z law) when flowing through inductors.

VL = – L (di/dt)

This opposition (- L (di/dt) will slow down the changes of current in the inductor. This process will lower the produced EMF across the inductor until the changes in current stable. This way, inductor will stop to oppose the current as changes in current is zero i.e. the energy storage in the inductor is over and the value of induced EMF.

VL = 0

At this stage, there is no resistance (opposition to flow of current through inductor) and the induced EMF is zero as well. This way, the inductor is acts like a conductor.

When the resistance or inductive reactance of the inductor is zero, then

IL = V /XL

If we put XL = 0, the current flowing through inductor would be infinite i.e. short circuit.

In short, the working principle of inductor is based on changing of magnetic flux, but there is no changing magnetic flux due to no frequency in DC supply. This is the reason why an inductor acts as a short circuit in DC supply.

## FAQ

### Why does inductor not work in DC?

Inductor works on the principle of changing flux, Since in a DC direction of current is constant so magnetic flux will not change. When DC is used in a circuit having an inductor the inductor will offer no impedance/resistance and it will behave as a short-circuited path

### What does an inductor do in an DC circuit?

In a dc circuit, an inductor acts like a short circuit when the current is constant. This means that the current flows through it without any voltage drop. In an ac circuit, an inductor acts like a resistor that depends on the frequency of the ac source

### Why does an inductor behave as simple wire for DC current?

An Inductor is equivalent to a short circuit to direct current, because once the storage phase has finished, the current, iL, that flows through is stable,IL=V/R no self induced e. m. f is produced and vL is zero

### Where does inductor behaves as short circuit?

Inductive reactance is infinite at t=0+, so the inductor behaves as an open circuit initially. Similarly for the inductor at steady state inductor behaves as a short circuit. At steady-state, the inductor behaves as a short circuit. A steady-state capacitor behaves as an open circuit

### Why is the inductor short circuit to DC?

An Inductor is equivalent to a Short Circuit to Direct Current, because once the Storage Phase has finished, the Current, iL, that flows through it is stable, iL = V / R, no Self Induced e.m.f. is produced and vL is zero. The Inductor acts like an ordinary connecting wire, its Resistance is zero

### Why is inductance ignored in DC motor?

The equivalent circuit of a brushed DC motor is quite simple. In most cases the inductance can be ignored because the electrical L/R time constant is usually much lower than the mechanical time constant given by the rotor inertia

### How does an inductor work as a circuit for DC supply?

In summary, an inductor acts as a short circuit for DC supply because it does not store energy in a magnetic field when DC voltage is applied to it

### Why does an inductor act as a conductor for DC?

an inductor acts as a conductor for dc. … Aninductor act as a conductor across a DCconnections because it has negligible resistance and it can’t store magnetic energy since there is no changing current flowing across the inductor

### Why does an inductor allow DC easily?

Inductor has a property to oppos the sudden change in current flow through it. In DC change in current in the circuit under normal operation is zero. So it can easily flow through inductor

## What is the Suitable Wire Size for 20A Breaker and Outlet?

How to Find the the Right Wire Size for a 20-Amp Breaker and Outlet Based on NEC? Choosing the the…

## Why Do We Need to Install a Starter with a Motor?

Why Do We Need to Connect a Starter with Electrical Motors? Essential and Need of Starter with Motor A starter is a device used…

## Why are Generators and Alternators Rated in kVA, Not in kW?

Why is an Alternator or Generator Rated in kVA, Not in kW? As we already know that why is a transformer…

## Why Does AC Need More Insulation than DC at the Same Voltage Level?

Why Does AC Voltage Require More Insulation than DC Voltage for the Same Working Voltage Level? For the same working…

## Why is a Power Plant Capacity Rated in MW and not in MVA?

Why is the Rating of a Power Plant Capacity Expressed in MW instead of MVA? For the following reasons, a…

## Why are Overhead Power Lines Loose on Electric Poles & Towers?

Why are Overhead Power Lines Loose on Utility Poles and Transmission Towers? Transportation of people, goods, and services today is…

## Why Radio Waves Are Chosen For Close Range Transmission?

Why Radio Waves Are Chosen For Close Range Transmission? INTRODUCTION Back then in the stone ages, information were disseminated either…