# How does Inductance varies with change in applied voltage with respect to time ?

1. Jul 26, 2012

### rahul.6sept

Dear all,

I would like to know how exactly the inductance varies with change in applied voltage with respect to time and if there is any mathematical relation for the same available.

Regards,
rc

2. Jul 26, 2012

### chutes123

V = L$\frac{di}{dt}$

Where V is voltage, L is inductance, i is current and t is time. There has to be a change in current else there will be no induced Voltage. So the greater the change in current, the greater the induced Voltage. Simple as that.

3. Jul 26, 2012

### Staff: Mentor

The inductance is constant, unless the current through the inductor exceeds the saturation current of the inductor.

4. Jul 26, 2012

### rahul.6sept

yes it was a typo, should have been applied current and not applied voltage.

1) But what will be effect in inductance in case of a piece of copper wire (considering hypothetically) whose radius changes when current flows through it ?

2) Also would like to know regarding the reply of berkeman ............... what actually happens when applied current exceeds the saturation current of the inductor.

Regards,
rc

Last edited: Jul 26, 2012
5. Jul 26, 2012

### Staff: Mentor

The wikipedia page gives a pretty good explanation of saturation. Basically the inductance drops for currents that approach ane exceed Isat...

http://en.wikipedia.org/wiki/Saturation_(magnetic [Broken])

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Last edited by a moderator: May 6, 2017