Inductance Meter

[Jimmy154]

lalena.com has a winding inductor calculator. Worked very accurately for me. Although you have to wind perfectly otherwise it will underestimate the number of turns. I can't wind perfectly so I usually wind a few more turns before I measure.

You might want to go with bigger diameter wire for sub. Also you might want to get a transformer type inductor for your sub, to significantly cut down on the number of turns.

You don't multiply by 2. That's just telling you the range, like you said. Ranged means from 0 to 2 mH is what it can measure, for example. They have the smaller ranges for improoved accuracey. You wouldn't measure your .33 mH on the 20 mH range. You would use the 2 mH range for better accuracey. Well atleast I would.

[extremy]

I wasn't sure how to read the ranges, for sure.

I'm almost done adding the turns for the larger coil, I have it up to 2mH. If this doesn't do what I think it should I'll go do more research, and if I find the answers needed, I'll buy the coil from Parts Express.

There's a method to figure out how many ohms a coil generates. I've so far missed that one too.

Thanks for your ideas,
Greg

[jomor]

A very easy and accurate way is to measure them using Speaker Workshop

[Ron E]

Originally posted by extremy

But, as I figure this formula from measuring what I have on my coil, this equation isn't even close. { Just my observation on this test. }

Any ideas welcome!
Greg

I have an idea, show us your calculation.

[extremy]

L = 0.8 * a² * N² / (6a + 9l + 10c) uH

N= 40 turns N²=1600
a= 1.0 ave. radius a²=1
c= .125 ht. Of windings
l= .625 length of coil

.8*1600*1=1280
6+5.625+1.25=12.875
1280/12.875=99.42uH

.8*1600*1/(6+5.625+1.25)uH

Their formula = 99.42uH

I measure .336uH on the LC meter.

This help?
Greg

[thomas997]

L/C Meter IIB is supposed to be very accurate.

But the kit cost is 100$, no idea what buying the parts alone would be..

So I just bought a B&K LCR meter off of ebay for less.