[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Windings vs. Diameter - errors

Original poster: Ed Phillips <evp@xxxxxxxxxxx>

One easy way to get a pretty good check on the total wire length is to measure the DC resistance and divide by the "table values" for resistance of that wire size. Knowing the wire length, diameter, and the OD of the form you can calculate the number of turns easily, remembering that the effective turn diameter is the OD plus the wire diameter. I've found it checks within a percent or so at the worst. Of course, just counting the turns as you wind is still the easiest and best way.


As for "Medhurst inductance", remember that there is more than one approximate formula, depending on the L/D ratio, and that there are simple and more accurate formulae readily available. Considering the effective operating bandwidth of our coils, is great accuracy of any interest other than as a subject unto itself?