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inductor

shopitham

Nov 30, 2010
5
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Nov 30, 2010
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Hai friends,

I am designing a circuit to measure the inductance of a coil. I have few basic ques.

1)Why inductance of a coil or inductor should vary with frequency, when it value is constant?
2) Do we have to specify the inductance value at a particular freq ?
 

shrtrnd

Jan 15, 2010
3,826
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Jan 15, 2010
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3,826
You can find a lot of circuits on the web for your design.
You need to change HOW you're thinking about the value of an inductor.
When inductors are made, manufacturers determine what standard inductance values they want to make. Their test frequency to create the line of inductors they will make is usually chosen where the inductance vs. frequency is relatively flat. That freq will be well below the self-resonant frequency of the inductor.
Power inductors are typically specified at 100KHz. Chip inductors are specified in the MHz frequencies.
When the mfgr actually makes the inductors of a particular product line, they are always stamped with the NOMINAL inductance stated in the device's data sheet. The manufactuer measures the inductance at their test frequency, and verify that the measured value is within the tolerance of the nominal marked value.
The inductance stamped on the inductor itself, is according to the parameters THEY established, and which they will list on a data sheet for their device.
So yeah, inductors ARE specified at a particular frequency.
The data sheet for the inductor, will tell you what the inductance for that particular device will be, at what frequency.
 
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