On 5/12/2010 3:16 PM, K7ITM wrote:
On May 12, 12:58 pm, wrote:
...
To see what I mean, try entering D=10mm, N=10, len.=20mm,
d=1mm, and check what C(L,p) is reported. Now try changing D in 1mm
increments up and down. OK, so I don't trust the reported C(L,p)
value, ...

OK, it also helps to RTFM. The text down below the inductance
calculator explains about this some. Also, I should have said that
you need to set the "design frequency" to something low (e.g. 10MHz)
to see the effect. However, the text suggests that C(L,p) value would
be larger than expected...and I've also seen it for some coils to be
considerably smaller. So I end up, then, not finding the lumped model
including C(L,p) being very useful for the things I do, where I want a
model that gives me _decent_ agreement over a broader frequency range,
rather than perhaps more exact agreement over a very limited frequency
range (as happens when the reported value of C(L,p) gets very large;
try "design frequency" = 1MHz for that coil).

Cheers,
Tom



You are amusing in an engineer unix geek kind of way. Just the kind of
thing that annoyed my ex.

tom
K0TAR