Joule Thief

[xee2]

@ jeanna

I do not know if you remember, but some time ago I gave you this formula for calculating inductance of coils on the 3.38" toroids. Now that you have an inductance meter it would be interesting to see how accurate it is.

For 3.38" toroids only:

millihenries = 0.01104 x (number of turns)^2


where the "(number of turns)^2"  means "number of turns squared"

[jeanna]

I count 27 turns
27 x 27 = 729
729 x 0.01104 = 8.048 mH

The meter reads 5.65mH

So, I did it again

4T
4 x 4 = 16T
16 x .01104 =0.1766mH

the meter reads
0.126mH

The problem I am having with the equation is it seems recursive to me.
If N= the number of turns then 7 turns = 7 and N²=49. But somehow it is supposed to be 49 x the inductance... but wait a minute I am solving for inductance??

aargh!

jeanna

[Mk1]

@ Mk1

Google gives this:

Iron-56 is the most common isotope of iron. About 91.754% of all iron is iron-56.

Thanks Xee

[xee2]

@ jeanna

For 3.38" toroids only:

millihenries = 0.01104 x (number of turns)^2


where the "(number of turns)^2"  means "number of turns squared"

The  0.01104 is suppose to be the inductance of a single turn. But it does not seem to be correct. You can make a similar equation for any toroid. Just measure the inductance of 10 turns and divide that number by 100. That should be the inductance of a single turn. Then the inductance of any number of turns can be found using:

inductance of N turns = (inductance of single turn) x (number of turns squared)

[jeanna]

Thank you xee2,

jeanna