Cecil,

There's a little check you can make on the accuracy of program SOLNOID3
regarding the self-resonant frequency of a solenoid.


The resonant frequency is due to the stray capacitance of the coil being in
shunt with the inductance.


The program allows the length of a coil to be stretched out until it is as
long as the wire it was wound with. Throughout the process, as L and C
change with coil length, the self-resonant frequency is calculated.


Resonant frequency is calculated up to the point when the original N turns
are stretched out into a straight length of wire. You can do a simple check
using your space-man's pocket calculator.


Does the program-calculated resonant frequency coincide with the resonant
frequency of the straight wire considered as a 1/2-wave dipole ?


Incidentally, when the coil is only partly stretched out, the program can be
used to estimate the resonant frequency of "Slinky's". Never having had a
Slinky I cannot say precisely how accurate this might be.
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Happy Xmas to you and yours and all that sort of thing.
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Reg.