coil help

[yasir_ali]

Hello Guys! i am just stuck on how to wind a coil. like i am have to wind a 22µH coil. so how to wind that?

i have read many books on how to wind the coil. A book told me a formula that L=N²µA/ l,
where;
L=Inductance in Henry(H)
N= number of turns of wire
µ=it is the permeability in Henry per meter (H/m)
A=it is the area cross-sectional area in meter square and
l= it is the core length in meter.

i don't know how to choose N,L,µ,A and l AND what gauge size wire i have to use, so that when i wind the wire according to that, i must have the required Inductance.? please help me wind a 22µH coil. and plus tell me that if there is any way to check that, what i wound a coil, has what amount of Inductance. mean How can i measure the inductance of the coil?

Thanks

 

[indulis]

What is the application? How much current do you need to pass? Is it a air, iron or ferrite core inductor?

 

[Hero999]

I found this calculator using Google.
Coil Calculator - Single-layer and mutil-layer coil calculation in javascript

I think you should use a ferrite core, in which case it's probably easier for you to but it.

If you make it by hand, an 22µH inductor will need 110 turns of 25 AWG wire wrapped round a 10mm former spanned over a 50mm length.

How much current does it need to carry?

25AWG wire is only good for 200mA or so.

 

[yasir_ali]

look at the picture i've attached. i have designed an Colpitts Oscillator. every thing went well But now i am just unable to wind a coil of 22µH for this circuit. How can i wind that should have inductance of 22µH? And on what assumptions we choose the core to be air, iron or what so ever?

 

[Hero999]

I've just told you, read the above.

 

[yasir_ali]

@ Hero
first of all i don't know how to choose a core that is best for the inductor. but as you said i should use the ferrite core. But if suppose i choose the iron or other core, so does it effect other parameters when the permeability of core also changing? i mean to say that does changing core means thet i'll have to change these parameter like will number of turns, length and other thing you told me ? if yes then How choose a core that is good for inductor's inductance or these values which this calculator is providing.

And i think i cannot make all 110 turns in 50mm area. so can i go for up on the turns i made?

 

[Hero999]

The datasheet for the core should give the permeability.

My calculations assumed an air core.

According to Wikipedia 25AWG wire can be wound into 22 turns per cm so in 5cm you can easily fit 110 turns.
American wire gauge - Wikipedia, the free encyclopedia

Why not just by a 22µH inductor? By the time you've bought the core and wire, you might as well had bought it in the first place.

 

[yasir_ali]

i can buy a 22uH inductor but i think that first i must know to make one. shouldn't i?
i am just hanging on last two questions that
1- i am not understanding that if i change the core what would be the values of turns and length i know they'll change. how to obtain them according to core. or if i use this calculator to find the other parameters for a specified inductance, i'll have to use a ferrite core all the time?

2- suppose 110 turn do not come in 50mm area (i know this time they'll come But just suppose). so should we have to go up on the same layer we just wind and continue winding?

 

[Hero999]

If you don't have enough space for a 50mm coil then use a two or three layered coil. The calculator I linked above can calculate inductances or the number of turns for multilayer coils.

 

[yasir_ali]

ok. Thanks a lot HERO. Thanks once again

 

[indulis]

If you were to wind it on a ferrite core... let's say a E core (E5.3) from Feroxcube, 3F4 material which has a inductance factor of 165 nominal, that would be 11.5 turns, or with 12 turns... 12²*165=23760nH or 23.76µH

 

[yasir_ali]

@ indulis
what? i did not understand. please come again

 

[indulis]

Inductance is turns squared mutilpied by the inductance factor.

N²*Al=L(nH)

 

[yasir_ali]

@ indulis

..........let's say a E core (E5.3) from Feroxcube, 3F4 material which has a inductance factor of 165 nominal...... ???????????????
I did not understand this. as i told before that i am vary new to the inductor even i understand till to wind with air core but how to wind with other cores. like you said for ferrite, we are using 165.what this 165 is? well please tell me. i wanna understand it.

Thanks

 

[stevez]

I am not an electronics expert but if faced with this challenge I would do the following:
A. Determine approximate frequency of operation. I'll imagine you want to work at 5 mHz.
B. Get my Amidon Associates handbook off the shelf.
C. Examine the applications section and there I would read that for an oscillator I'd use an iron powder material. This is consistent with what I see others using for oscillators.
D. I'd read in the section about iron powder that Material #2 could be a good choice and I'd learn it's available in toroidal form.
E. I'd examine the charts for the various sizes and calculate the number of turns. Be careful, you need to be sure you can fit the number of turns required on the core.

I hope this helps.

 

[indulis]

Here is the data sheet...

On the second page you will see that for this core shape with 3F4 material, it has an "inductance factor" of 165 ±25% (that is why I said 165 nominal). Which brings you right back to inductance is the number of turns squared mutilpied by the inductance factor and the result will be in nanohenrys.

N²*Al=L(nH)

So, with 12 turns wound on this core, with 3F4 material, you will get... 12²*165=23760nH or 23.76µH

If you had chosen 3F3 material instead, which has an inductance factor (Al) of 265, those same 12 turns would give you... 12²*265=38160nH or 38.16µH

 

[yasir_ali]

@indulis

hey indulis! i am totally confuse about this Al. i am not understanding that what is this "Inductance factor" is. please don't mind and tell me. or give me like to pdf which can briefly explains me this.

Thanks

 

[indulis]

Look on page 26...

https://www.electro-tech-online.com/custompdfs/2010/04/Ch13slide.pdf

 

[yasir_ali]

Today i just wound an inductor on a nail. that was rough. mean i did not count the turn number and length of the coil. i just wanted to start with inductor. i also wound second winding on it. as you can see in pic "Inductor". the White (First ) wire is on the core (nail) and Green (second) wire is on the white wire.
first i applies D.c Voltages with my 6v Battery, it created a strong magnetic field,But did not induced any Voltage (i know why.i just wanted to confirm it ).

Then i applied A.c voltage using a transformer (a transformer in figure Transformer1 which has orange wire coming out of it) which was steeping down the voltage form 220v to 10v but when i connected it to the inductor, the inductor did not induced any voltage on the second (green) wire. and when i checked the voltage at the output of Transformer, the meter was showing 0v.and the Transformer got so HOT.Then i removed first Transformer and connected a second Transformer to the inductor, which steps down voltage from 220v to 8.5v.when i connected this second Transformer to the inductor, the voltage of this Transformer dropped to 3v and the magnetic field was so poor and there were no induced voltage with this transformer too.and finally i just saw some smoke. so i decide to disconnect inductor from transformer. The The second Transformer is shown connected in figure Transformer.

 

[indulis]

You did not have enough inductance... the "nail" saturated and you just had a short circuit of a few turns of wire.