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Why voltage lead when alternating current through inductor?

2007-02-12 12:39:16 · 4 answers · asked by Muhammad A 1 in Science & Mathematics Physics

4 answers

An inductor resists allowing changes in the current through it. It can't prevent it from changing in response to a changing voltage, but it slows the change. If you suddenly apply 10 vdc across a 10 ohm resistor, 1 amp will start to flow immediately. If you do the same thing when an inductor (with 0 ohms of resistance) has been added in series with the resistor, the current will slowly increase to the 1 amp level.

With an ac voltage, this continually happens. The current starts to adjust to a change in voltage but before it gets to its final value the voltage has changed so much the current has to start adapting to new conditions again. The current continues to chase the amount of current that would result from the Ohms law current that would result from Vinstantaneous=I*R (where R is the pure Ohm part of the resister inductor series circuit).

So voltage leads because current is slow to adjust to voltage changes.

2007-02-12 14:38:18 · answer #1 · answered by sojsail 7 · 0 0

Because depending on the value of the inductor, you will need a given amount of time for the voltage to induce a current through the inductor, based on the voltage and inductance. This is because the unenergized inductor has a static magnetic field to overcome, which acts as an inhibitor to changes in current. Once the time constants have elapsed, the inductor has a new level of magnetic field, which will again react to changes in current by inducing a voltage across it. The voltage it induces is dependant on the rate of change of current and the value of inductance.

2007-02-15 05:28:53 · answer #2 · answered by joshnya68 4 · 0 0

Okay, you got the part that the Inductive Reactances and Capacitive Reactances are of equal magnitude. Since the capacitor and inductor are in parallel, the Voltage across them are the same. Their currents however are "out of phase" from each other. The current in the inductor "Lags" the Voltage applied by 90 degrees while the current in the capacitor "Leads" the Voltage applied by 90 degrees. So there is 180 degrees of phase shift between them, which sounds like they would be in phase.

2016-05-24 03:09:05 · answer #3 · answered by Anonymous · 0 0

very confusing stuff. query with bing and yahoo. it can help!

2014-11-14 20:19:05 · answer #4 · answered by brian 3 · 0 0

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