# what is inductance?

Discussion in 'Physics' started by antennaboy, Oct 16, 2008.

1. ### antennaboy Thread Starter Active Member

Jan 31, 2008
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I am not clear on what inductance means. can we simply say that it quantifies the opposition to a change in current due to a magnetic field?

thanks

2. ### Papabravo Expert

Feb 24, 2006
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1,850
In strictly mathematical terms it is a constant of proportionality that relates the time rate of change of current(di/dt) with a voltage drop(V).

In physical terms it is a property of conductors. Even a length of wire has inductance. Wound in a coil, the magnetic field produced by an alternating current is many times greater than the field around a straight conductor.

3. ### Ratch New Member

Mar 20, 2007
1,068
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antennaboy,

Incomplete definition. If a change of current in a circuit magnetically induces a voltage in the same or different circuit, we have magnetic induction. Inductance is measured by the ratio of the induced voltage to the rate of change of the inducing current.

Ratch

4. ### Metalfan1185 Active Member

Sep 12, 2008
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A Sudden Voltage drop on a coil causes the magnetic field to collapse and, like a transformer, make a high voltage spike on one end of the coil. If you ever connected a solenoid to a power supply and then disconnected one wire by hand, then you know what im talking about.

I have always played with electronics by hand, so there may be lots of little technical math bits and pieces that i dont know (yet, but im workin on it) but i have plenty of practical hands on expierience...i also have plenty of burnt out components and have had my share of shock treatment.

5. ### scubasteve_911 Senior Member

Dec 27, 2007
1,202
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Strictly speaking, inductance is the ratio of flux linkage to current. Using the quantity in electronic circuits, we can say the voltage drop across the inductance is the proportional to inductance multiplied by the time-rate of change of current.

V = L di/dt

Steve