Adjusting conductor values

[cpconner]

I have some left over conductors that I would hate to waste in a new build and am wondering if someone can help me determine if I can accurately adjust the mH to fit my needs. I have a 2.0mH 20 awg air core inductor that I want to unravel to 1.5mH. Any idea how much to take off or should I just buy a new 1.5mH inductor for accuracy? Any help is appreciated!

[a4eaudio]

What measurement tools do you have? DATS can measure the inductance. I believe some (all?) multimeters can too.

[wogg]

Parallel post... great minds think alike

[wogg]

You'll need DATS or a inductance meter to be sure. There are formulas for calculating inductance based on turns, length and width of the coil but you'll be guestimating.

Best bet would be unwind, measure, unwind some more etc.

[Billet]

I used a gram scale to adjust inductors before I had any other way to measure them. I think if you weigh the 2 mH and multiply by 3/4 and then unwind it to the new weight, it will be reasonably close to 1.5 mH.

[billfitzmaurice]

That's not going to give an accurate result. For a given coil length what determines inductance is the number of wire turns squared, which isn't linear with respect to the weight of the wire.

[AEIOU]

What measurement tools do you have? DATS can measure the inductance. I believe some (all?) multimeters can too.

I have several DMMs, from cheap to expensive, none of which measure Inductance. Capacitance measure is very common with DMMs, but not Inductance. I do however have a digital LCR Meter and they are very affordable.