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 ...

# Inductance calculations

Started by ●August 20, 2019

Reply by ●August 20, 20192019-08-20

On Tue, 20 Aug 2019 15:07:07 +0100, Peter Percival <peterxpercival@hotmail.com> 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 ...of course there are. Your google is broken? 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."

Reply by ●August 20, 20192019-08-20

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,> http://www.mogami.com/e/cad/coil-01.htmlIf you want a deep understanding, with Nagaoka.> http://mathscinotes.com/wp-content/uploads/2014/04/lundin_Proc_IEEE_1985.pdfOtherwise, dig into these. Or just the first one.> http://crystalradio.net/professorcoyle/professorcoylecyl.shtml> 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=10use the second on this page.> 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 The ones I have used is Professor Coyle, and I had a downloaded version, so haven't tried the online version and electronbunker. Mikek

Reply by ●August 20, 20192019-08-20

amdx wrote:> 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, > >> http://www.mogami.com/e/cad/coil-01.html > > > If you want a deep understanding, with Nagaoka. >> http://mathscinotes.com/wp-content/uploads/2014/04/lundin_Proc_IEEE_1985.pdf >> > > Otherwise, dig into these. Or just the first one. > >> http://crystalradio.net/professorcoyle/professorcoylecyl.shtml > >> 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 >> > > use the second on this page. > >> 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 > > The ones I have used is Professor Coyle, and I had a downloaded version, > so haven't tried the online version and electronbunker. > > Mikek >Ooh, there's lots! Thank you.

Reply by ●August 20, 20192019-08-20

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 ...If your getting into crystal radio, You might find this interesting,> http://theradioboard.com/rb/viewforum.php?f=2and this overwhelming,> http://makearadio.com/crystal/index.phpMikek

Reply by ●August 21, 20192019-08-21

A first approach : µ0*N^^2*S/L. Parasistic elements are uncomputable. Peter Percival a écrit le 20/08/2019 à 16:07 :> 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 ...