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
