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I NEED HELP MAKING A 0.35mH INDUCTOR? Answered

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user
icengBest Answer (author)2012-12-14
RE-POSTED by  Request :-O)

Here are some results ;
  • L inductance = 350 uh
  • Diameter of coil = 2.05"
  • Number of turns = 80
  • Gauge of magnet wire = #29
  • length of coil = 1"
See the graphic table..
BTW the wire gauge can be a larger number = smaller diameter.
A gauge of #29 single layer coils of wire will be an inch long.

A

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user
Ehsan AliS (author)2015-03-22

how i build 1 milihenery inductor ..

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user
pratikshap8 (author)2014-02-15

i want to make same circuit of fm receiver.wanted to knw how many turns should be made of 29 guage wire.i was searching for how much guage.thx for d answr given by u in earlier posts.

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pranjal12 (author)steveastrouk2012-11-13

I am trying to make a FM receiver i needed it for that . Here is the schematic.

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iceng (author)pranjal122012-11-14

OK, now I can help, this is a bare wire air core and will probably be just
a few loops hand turned and tuned by pulling them apart of squeezing
the loops together.

BTW this is a high frequency tuning inductor.

I will try to get you a wire size, a loop diameter and the number of turns
to make this coil inductor soon.

Can you provide the article where you found this schematic ?
It may save me a bunch of tables work by referring to an available
RF coil or mention how to make that..

A

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iceng (author)iceng2012-11-14
Here are some results ;
  • L inductance = 350 uh
  • Diameter of coil = 2.05"
  • Number of turns = 80
  • Gauge of magnet wire = #29
  • length of coil = 1"
See the graphic table..
BTW the wire gauge can be a larger number = smaller diameter.
A gauge of #29 single layer coils of wire will be an inch long.

A

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samaddon (author)iceng2013-06-26

Hey ! iceng "wire gauge can be a larger number"
i am pretty confused from this word . what i know the small the diameter of the wire the larger is the gauge (in numbers) am i right?
and can you please tell me what will be the diameter of the coil if i use a #18 gauge wire? Thank's in advance for your help.

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iceng (author)samaddon2013-06-26

Yes you are right !  Look here.

18 gauge wire is 1.024 mm thick.
80 turns will be 80×1.024×1.1slop = 90 mm = 3.54" minimum coil length
but the monograph has determined a 1" length

So lets try 70 turns × 1.024 wire dia × 10% = 78 mm = 3.1" coil length
K is now 3
coil length = coil dia / K = 2.05/3 = 0.68"
This is a worse diverging solution :-(

Next try a line through 350 uH to a 3" dia coil intersecting the Axis at 4.5
Using 80 turns through the 4.5 axis results in a K of 1.1
Coil length = coil dia / K  = 3 / 1.1 = 2.72"
this solution is converging to 3.54" which is the actual physical windings.

Now try a line through 350 uH to a 4" dia coil intersecting the Axis at 4.9
Using 80 turns through the 4.9 axis results in a K of 0.83
Coil length = coil dia / K  = 4 / 0.83 = 4.8"
this solution could work by spacing the actual physical windings but is too large.

Zero in with  a line through 350 uH to a 3.5" dia coil intersecting the Axis at 4.8
Using 80 turns through the 4.8 axis results in a K of 0.9
Coil length = coil dia / K  = 3.5 / 0.9 = 3.8"
This solution will work by loose spacing the actual physical #18 windings.

COIL  ( Diameter = 3.5"  Length = 3.8"  Gauge = 18  Inductance = 350 uh )

This is a single layer coil solution.
There are monographs for multiple layer coils that require machine
winding precision  and are smaller.

A

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samaddon (author)iceng2013-06-26

Thanks you've really solved my problem i was confused!

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user
iceng (author)samaddon2013-06-26

Good to hear.

You need to hire  EE teachers  to start exposing you to DC and AC circuit theory
and the math is simple.
Power semiconductors SCR, TRIAC, MOSFET,  BIPOLAR,
VACUUM TUBES are making a comeback, Li battery theory,
DC motors, Stepper, Induction, Synchronous, Traction and Homopolar motors.

Your probably do are not challenged by your environment except by females :-) 

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pranjal12 (author)iceng2012-11-15

Hey thank you very very much here is the article where I found it-
http://www.circuitstoday.com/single-transistor-radio

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user
iceng (author)pranjal122012-11-15

The text confirmed the winding data I texted you :)

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pranjal12 (author)iceng2012-11-16

I'm grateful to u very much.
Thank u.

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mrmerino (author)pranjal122012-11-13

That looks like it's tapped in the center. You might find two .16 nh inductors and connect them together with the tap connected where they meet.

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steveastrouk (author)mrmerino2012-11-14

Won't work: Its more of a transformer when its tapped.

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steveastrouk (author)pranjal122012-11-13

Ah ! You CAN buy them, they're used in power supply filters, and it MAY be worth seeing what a PC powersupply might reveal.

Otherwise, you need to find a small "ferrite toroid" and wind your own.


Are you sure that's an FM receiver ? It looks more AM to me.

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pranjal12 (author)steveastrouk2012-11-13

Ya i have ferrite toroids but u know I really dont know what diameter wire to use and how many turns of it. I needed help on that.

And i have those circuits but they are of u knowor 5mH or
1.35mH

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steveastrouk (author)pranjal122012-11-13

Diameter of wire here doesn't really matter.
to use a toroid, you have to know its "Al" value, which isn't something you'd generally get at the local shop !

The simplest thing to do would be to wire, say 10 turns on it, and make it oscillate with a signal generator against a capacitor, the inductance is then Al x n^2, where n is the number of turns, and you can deduce Al.

Steve

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pranjal12 (author)steveastrouk2012-11-14

Thanks a lot! I would try it and come back to you.

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iceng (author)steveastrouk2012-11-12