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    how to measure inductance

    Can somebody tell which instruments are needed to measure the inductance and Q of a spiral inductor and active inductor? how to measure it?

    Thanks.

    Best regards,
    chunlee

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    measuring inductance

    you can use a network analyzer. You can determine the Q value from group delay obtained from the network analyzer.


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    how to measure inductance of coil

    Hi,


    latest technology of Fluke Instruments (the Digital Multi Meter that is)
    can measure capacitance, charges (in coulombs) and inductances

    Hey, I use Fluke!


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    inductor measurement

    One of the easiest ways of measuring L is to build an LC oscillator with known capacitance, measure frequency and calculate the inductance from the common LC-tank equation: ω=1/√LC --> L=1/ω²C, where ω=2Πf ..
    See circuit below ..
    Regards,
    IanP


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    measure inductance of a coil

    Q meter is mostly used for the measurement of inductance and Q of circuit



    •   Alt23rd December 2005, 06:02

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    how to measure inductance of a coil




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    measure inductance

    hi boy,

    can u pls tell how to measure inductance and Q using network analyzer?
    or send me some document about it?

    Thanks.



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    measuring inductance of a coil

    You can build an easy microcontroller based L/C meter
    here is it..

    I hope it helped.
    Ahmad


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    inductance measurement method

    Quote Originally Posted by chunlee
    hi boy,

    can u pls tell how to measure inductance and Q using network analyzer?
    or send me some document about it?

    Thanks.
    The NA is a rather expencive & very rare instrument. You'd better try some LC-Q meter which are much easier to find.



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    how to measure inductor

    VNA may measure L (and or C) but it's poorly accurate, especially on the Q determination.

    Qmeter, when used in conjunction with Standard inductances is the most accurate instrument.
    Qmeter give L, Q, SRF.



    •   Alt28th December 2005, 21:16

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    measure inductance coil

    Quote Originally Posted by sergio mariotti
    VNA may measure L (and or C) but it's poorly accurate, especially on the Q determination.

    Qmeter, when used in conjunction with Standard inductances is the most accurate instrument.
    Qmeter give L, Q, SRF.
    Why did you comment so ? When you short circuit of an inductance, you'll get "very accurately" R and X so then to find inductance value and its associated Q factor are not difficult.

    Because in RF region, inductances and capacitances are not flat responded and in my opinion an inductance or capacitance should be measured at the frequency of operation (or closer to )

    But essentially, Q factor measurement equipments can not reach very high frequencies and their results are therefore not indicative.



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    how to measure an inductor

    hi everyone,

    I'm intend to measure my inductor on wafer at frequency around 2.4GHz. So i think the VNA is suitable for me. Can someone pls briefly tell me the procedure to characterize the inductor? (spiral and active inductor)

    Thanks.



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    fluke inductance meter

    Quote Originally Posted by BigBoss
    Quote Originally Posted by sergio mariotti
    VNA may measure L (and or C) but it's poorly accurate, especially on the Q determination.

    Qmeter, when used in conjunction with Standard inductances is the most accurate instrument.
    Qmeter give L, Q, SRF.
    Why did you comment so ? When you short circuit of an inductance, you'll get "very accurately" R and X so then to find inductance value and its associated Q factor are not difficult.

    Because in RF region, inductances and capacitances are not flat responded and in my opinion an inductance or capacitance should be measured at the frequency of operation (or closer to )
    I try to answer BigBoss and chunlee both.

    The accuracy of VNA measurement is set mainly by Standards, that are usually very accurate jewels, and often the residual accuracy is of the order of +/-0.02...0.05 (number! not dB). But, when you try to measure very reactive devices (i.e. near to the boundry of the Smith Chart) , a small uncertainty like +/-0.02 , will became a large uncertainty on Q determination . I don't provide here the formulation, see Agilent AN-95.

    Qmeter has a different principle of operation. It read the resonant extravoltage.

    But if the practical measurement needs are on wafer, there is no choices. Both VNA and on-wafer Standards are required.

    Answering chunlee, set the VNA to display a Smith Chart on the screen. If necessary set marker parameters to display R+jX. I know that is possible on Agilent 87xx and 8510. Q=|X/R|

    Since the accuracy on-wafer will be not very high, my suggestion is that the user should propagate the uncertainty equation to give an evaluation of the instrumental uncertainty.
    Agilent provide a free and useful MS Excel speadsheet to evaluate uncertainty. look for "VNAUncert"



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    measuring coil inductance

    What is the best way for measuring the inductance of a small planar coil inductor (i.e. RFID tag) ?

    Would it be OK to use the VNA method for this? i.e. connect both terminals of the coil to a 50 Ohm bnc connector and measure it that way?

    OR

    Is there a better suited method? i.e. involving a signal/function generator?


    Regards

    Cat



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    measure coil inductance

    Quote Originally Posted by chunlee
    hi everyone,

    I'm intend to measure my inductor on wafer at frequency around 2.4GHz. So i think the VNA is suitable for me. Can someone pls briefly tell me the procedure to characterize the inductor? (spiral and active inductor)

    Thanks.
    After doing two ports S-parameter measurement, transform S-matrix into admittance (Y) matrix, you can calculate Q and L using:

    Q=-Im[Y(1,)]/Re[Y(1,1)]

    L=Im[1/Y(1,1)]/ω

    I am not sure whether there is difference between the calibration procedure of passive inductors and active inductors.

    Regards,



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    find inductance

    Treat the inductance as a two-port network, and you can measure the s parameter,
    and you can deduce the L from the S parameters.
    Perhaps not accurate.



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    s parameter inductance

    Hi,

    To measure the inductance of a coil is the following method reasonable?

    1. Connect coil to DC voltage supply and measure the current
    2. Calculate the DC resistance
    3. Connect coil to an AC voltage suuply with known voltage and frequency, measure the current.
    4. Calculate the Impedance
    5. Calculate Inductive Reactance using results from steps 2 and 4.
    6. Calculate the Inductance using the result from step 5.


    Would this be accurate?


    Regards

    Cat



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    how to find inductance

    Hi all,
    I got a problem when re-draw S-parameters after de-embedding procedure.
    I used ADS to re-draw Smith chart of an on chip spiral inductor.

    - 1st, I used GSG probe tip to measure spiral (DUT) not very high frequency (50MHz --> 10GHz). Here I got S_measured values.
    - 2nd, I measured inductor test-fixture only (open standard). Here I got S-open values.

    Since I got the S-parameters data, I used ADS to convert S into Y data (S_measured ==> Y_measured & S_open ==> Y_open).
    Then, took: Y_mo = Y_measured - Y_open
    Finally, Y_mo data were reconverted into S-parameters and plotted in Smith chart.
    But in here, the Smith chart was not as I expected.
    Please take a look at 2 pictures following:

    Is there any body give me an advice? I really appreciate any your help.
    Thank in advanced! ^_^



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    fluke inductance

    Can you connect the same to a connector directly-both ends of the inductor and measure S11 to find L?



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    coil inductance measurement

    The problem is lying at that you Ymo=Y_meas-Y_Open, after that, the Y you got still include 50 ohm (system impedance) in series. That is why it looks so strange.

    Hope it help!

    Laipi



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