How to measure an inductor?

Discussion in 'Home Theater Projects' started by RichardHOS, Jul 8, 2003.

  1. RichardHOS

    RichardHOS Second Unit

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    Is there a way to measure an inductor accurately? My multimeter doesn't have any way to do this that I can see. I know I've seen some that have ways to measure capacitance (I think), but I'm not sure if they do inductance or not.

    Any thoughts? There aren't any markings at all to go by.
     
  2. Allen Ross

    Allen Ross Supporting Actor

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  3. Brett DiMichele

    Brett DiMichele Producer

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    There is a formula for measuring Inductors using a good
    multimeter and a 1% Tolerance Resistor (for accuracy). I
    do not know the forumula off hand but perhaps someone will
    chime in here that does. If not, go to www.diyaudio.com then
    go to the loudspeaker section and do a search for Measure
    Inductor I know there was a recent post about it..

    But idealy an L/C/R Meter or Bridge would be ideal [​IMG]
     
  4. Michael R Price

    Michael R Price Screenwriter

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    What you need is a voltage divider with the inductor in question plus a reasonably sized fixed resistor driven by an AC signal to measure the impedance at a couple frequencies. Subtract the DCR and you're left with the inductive reactance, which is simply a combination of the inductance and frequency. The impedance at any given frequency is the DCR plus 2pi*F*L, right? There's probably a better way, but that's the method that came to mind.
     
  5. NikhilC

    NikhilC Auditioning

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    For crossover-value inductors and capacitors, Speaker Workshop can be accurate to around 1%, and is free.

    There are also schematics around the web for inductor/capacitor measurements with DMM's, though this route would be more useful if you'll be measuring parts outside of the range in which Speaker Workshop works well. Check the bottom of this page for the useful range of SW.

    HTH,
    Nikhil
     
  6. RichardHOS

    RichardHOS Second Unit

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    eh... that parts express meter looks like the easiest way. [​IMG]

    Thanks for the suggestions. I was actually able to get the manufacturer to supply the information I needed (speakers manufacturer that is). I think I'll still get the LCR meter... looks like it could come in very handy.
     

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