How do I measure an inductor coil without a LRC meter?

[Jeff M.]

Good afternoon. So am running into an issue. Am trying to find out what value of an inductor coil is? I could unwind it but, it seems a lot of work for something that I could measure. So I don’t have a frequency generator and I have a few multi meters but, not a LRC meter. How would I go about measuring this inductor coil? I could but, a LRC meter like from B&K and is at $400.00 or I could buy the Dayton Audio Dats L.A. for $499.99. Also fluke has one but? it’s around $450.00. I was hoping not to spend at lot. Should I buy a no name brand on Amazon? Just need some advice. Thanks Jeff

 

[RickS]

The $130 version of DATs will do.

 

[MAB]

Good afternoon. So am running into an issue. Am trying to find out what value of an inductor coil is? I could unwind it but, it seems a lot of work for something that I could measure. So I don’t have a frequency generator and I have a few multi meters but, not a LRC meter. How would I go about measuring this inductor coil? I could but, a LRC meter like from B&K and is at $400.00 or I could buy the Dayton Audio Dats L.A. for $499.99. Also fluke has one but? it’s around $450.00. I was hoping not to spend at lot. Should I buy a no name brand on Amazon? Just need some advice. Thanks Jeff

With REW you can do it for free (just need a resistor and some wire, and a laptop with a sound card).

A DATS will do it for just over $100.
edit, as Rick just said...

 

[DVDdoug]

So I don’t have a frequency generator

Audacity and your soundcard can generate test tones.

Just make sure you don't put too-low of an impedance load on your soundcard or amplifier.

...Or just buy some new inductors of the value you want/need.

 

[Philbo King]

It depends a lot on the inductors intended use. A 50 kg 5000H power line inductor might require a different approach than a 4 nH SMD inductor intended as a 12GHz choke.

 

[RickS]

If just a crossover inductor, the Proster LCR meter on Amazon is only $34.

As @MAB mentions, you could use REW with some work, but would only trust if you can measure a known value to validate.

 

[Cbdb2]

These are all over the web. I bought one works great. $25 Cnd.

LCR-T4 TRANSISTOR/ESR/DIODE /TRIODE TESTER

transistor tester/ ESR table / LCR / frequency meter / square wave generator

leeselectronic.com

 

[SSS]

Question is how accurate the inductor should be measured, especially if it has a magnetic core. So called air core ones do not alter the measured value according to the measurement level (current and voltage). Simple measurements do not take account to the wire resistance and capacitance of the coil. Therefore it is hard to tell which measurement procedure and instrument is good for a specific inductor. Sorry, no easy answer possible. It has a reason that accurate RLC measurement instruments have a relatively high price in comparison to a digital voltmeter.

 

[Jeff M.]

Wow lots of answers. I did get it has almost no resistance from my multi meter. The dats I just sold not long ago and thought I was never going to use it. . Man what a bummer. I will have to ponder what I will do next? Thanks for everyone’s help. Jeff

 

[RickS]

Seems either spend your time to do with REW or spend $34 on the Proster LCR. Like the SMT component probes on that Proster. If they are any good, worth it just for them.

 

[Speedskater]

If you are good at math and have a DMM with good frequency response.
Make a series circuit of a resistor and the coil.
Selectric a frequency and a resistor value so the the voltage across the resistor and the coil is the same.
Then do the math.

 

[Philbo King]

If you are good at math and have a DMM with good frequency response.
Make a series circuit of a resistor and the coil.
Selectric a frequency and a resistor value so the the voltage across the resistor and the coil is the same.
Then do the math.

The math, in case you aren't aware:
R/(2 PI F) = L
R: resistor value in Ohms
F: freq in Hz
L: inductance in Henrys

 

[RickS]

As I indicated, liked the Proster probes enough to order one. I arrived today and did a quick test with 5 known inductors and measured them all correctly.