Why current lags voltage in inductor

Therefore, the value of constant C must be zero here in our case. But now we will discuss the same aspect but in analytical way.

For analytical discussion we will assume steady state condition. As we know that when a current flows through a solenoid, a magnetic field is created by the solenoid which remain confined inside the solenoid only. Now suppose, the current through the solenoid is changing with time, that simply means that magnetic flux will also change resulting into change in magnetic flux.

Here the cause is current flowing through the solenoid, therefore the emf will be induced in such a direction to oppose the flow of current. Here solenoid is Inductor. Let us consider steady state where the supply voltage V is going positive from zero point P in the figure below. In this case, as the back emf of inductor will also be zero and therefore the current flowing through the circuit will be maximum. If you apply a ramping waveform of current to the coil it produces a ramping magnetic flux and across the terminals of the inductor the voltage will be constant.

That constant voltage is proportional to the rate of change of flux. You might be able to see that this is mathematical differentiation so, applying a sinusoidal current through the coil from the current source produces a voltage that is the differential of the sine wave across the terminals.

That means the voltage is a cosine and thus, in AC analysis the voltage and current are displaced by 90 degrees. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Learn more. Ask Question. Asked 3 years, 6 months ago. Active 3 years, 6 months ago. Viewed 3k times. Wesley Lee 7, 6 6 gold badges 31 31 silver badges 50 50 bronze badges. Too sleepy to remember right now. We just like to say so because it makes the math easier. Show 5 more comments. Active Oldest Votes. This behavior is described by Len'z Law. Add a comment. Matt Matt 1 1 gold badge 4 4 silver badges 6 6 bronze badges.

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