 # Inductance calculations

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Peter Percival
Guest

Tue Aug 20, 2019 3:45 pm

Somewhere there must be a formula for the inductance of a hand-wound coil.

Air core, one layer of wire (of given swg) close-wound, diameter of
former (cardboard, probably inside of toilet paper roll), length of
coil,... (what else?), therefore inductance equals ...

default
Guest

Tue Aug 20, 2019 5:45 pm

On Tue, 20 Aug 2019 15:07:07 +0100, Peter Percival
<peterxpercival_at_hotmail.com> wrote:

Quote:
Somewhere there must be a formula for the inductance of a hand-wound coil.

Air core, one layer of wire (of given swg) close-wound, diameter of
former (cardboard, probably inside of toilet paper roll), length of
coil,... (what else?), therefore inductance equals ...

BTW single layer solenoid-wound coils usually hit the calculate values
spot-on, it doesn't start to get hairy until you add layers. There's
a formula that takes into consideration the diameter/length ratio too,
but for simple single layer coils try the "Amateur Radio Handbook."

amdx
Guest

Tue Aug 20, 2019 8:45 pm

On 8/20/2019 9:07 AM, Peter Percival wrote:
Quote:
Somewhere there must be a formula for the inductance of a hand-wound coil.

Air core, one layer of wire (of given swg) close-wound, diameter of
former (cardboard, probably inside of toilet paper roll), length of
coil,... (what else?), therefore inductance equals ...

Yep a dozen.
I have spreadsheeet labeled the Nagaoka Formula that is supposed to be
very accurate. You can search for it, But I think these use his formula,

Quote:

If you want a deep understanding, with Nagaoka.

Otherwise, dig into these. Or just the first one.

Quote:

http://electronbunker.ca/eb/InductanceCalc.html

> https://www.translatorscafe.com/unit-converter/ja/calculator/coil-inductance/?D=2&Du=cm&l=1&lu=cm&N=10

Quote:

That's enough so you will never know who is correct I ecpect

so haven't tried the online version and electronbunker.

Mikek

Peter Percival
Guest

Tue Aug 20, 2019 10:45 pm

amdx wrote:
Quote:
On 8/20/2019 9:07 AM, Peter Percival wrote:
Somewhere there must be a formula for the inductance of a hand-wound
coil.

Air core, one layer of wire (of given swg) close-wound, diameter of
former (cardboard, probably inside of toilet paper roll), length of
coil,... (what else?), therefore inductance equals ...

Yep a dozen.
I have spreadsheeet labeled the Nagaoka Formula that is supposed to be
very accurate. You can search for it, But I think these use his formula,

If you want a deep understanding, with Nagaoka.

Otherwise, dig into these. Or just the first one.

http://electronbunker.ca/eb/InductanceCalc.html

https://www.translatorscafe.com/unit-converter/ja/calculator/coil-inductance/?D=2&Du=cm&l=1&lu=cm&N=10

http://www.circuits.dk/calculator_single_layer_aircore.htm

http://www.66pacific.com/calculators/coil-inductance-calculator.aspx

https://coil32.net/online-calculators/one-layer-coil-calculator.html

https://hamwaves.com/inductance/en/index.html#input

https://www.qsl.net/in3otd/indcalc.html

https://knowpapa.com/inductance/

That's enough so you will never know who is correct I ecpect

so haven't tried the online version and electronbunker.

Mikek

Ooh, there's lots! Thank you.

amdx
Guest

Tue Aug 20, 2019 11:45 pm

On 8/20/2019 9:07 AM, Peter Percival wrote:
Quote:
Somewhere there must be a formula for the inductance of a hand-wound coil.

Air core, one layer of wire (of given swg) close-wound, diameter of
former (cardboard, probably inside of toilet paper roll), length of
coil,... (what else?), therefore inductance equals ...

You might find this interesting,
Quote:
and this overwhelming,

Mikek

Look165
Guest

Wed Aug 21, 2019 11:45 am

A first approach :
µ0*N^^2*S/L.
Parasistic elements are uncomputable.

Peter Percival a écrit le 20/08/2019 à 16:07 :
Quote:
Somewhere there must be a formula for the inductance of a hand-wound
coil.

Air core, one layer of wire (of given swg) close-wound, diameter of
former (cardboard, probably inside of toilet paper roll), length of
coil,... (what else?), therefore inductance equals ...

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