Of the second kind, order 0; solution to the field outside the helix. Source: Dr T. Dekker Since such an equation cannot be solved by ordinary analytical means, the present calculator will determine the phase velocity β of the lowest order (n = 0) sheath helix mode at the design frequency using ’s 12–14 combined - numerical root finding technique.
'Coil32' is a free coil inductor calculator, that allows calculating: single-layer and multilayer air core inductors, toroidal air core coil inductance.
For this calculator, a 15 of Dekker’s algorithm was translated by to, and then from there by yours truly to.A similar algorithm is also employed to home in on the frequency for which the coil appears as a quarter wave resonator. This is the first self-resonant frequency of the coil. Voltage breakdown of the air at one end of a Tesla coil. Source: The calculated inductance is negative; Can this be right?You are operating the coil above its first self-resonant frequency. A coil with an electrical length in-between 90° and 180° (and odd multiples of this) will behave like a capacitor instead of an inductor. This is once more an indication that the first self-resonance of a coil is in fact a parallel resonance. Because of its capacitive behaviour, the coil’s inductance will be stated as negative in this range.
Stray capacitance C p is much higher than that of other calculators; Can this be right?The concept of stray capacitance is what it is; a correction element in a coil’s lumped circuit equivalent to deal with the frequency independence of an inferior geometrical inductance formula. 7By employing helical waveguide-based formulas, the present calculator performs much better at estimating inductances at high frequencies. Therefore, the calculator compensates the lumped circuit equivalent even more so than other calculators. This results in higher values for C p.At the end of the day, the old-fashioned concept of a lumped circuit equivalent is better done away with. Instead, focus on the effective values at the design frequency for inductance, reactance, series resistance and unloaded Q.
What is the problem with designing coils using EZNEC?The pragmatists among us would probably like to employ, an antenna modelling program, which allows you to define in a very user-friendly way helical coil structures. However, this valuable method is not without its pitfalls:. Coils in EZNEC are defined as polyline structures. The projected polygon of the polyline should have the same area as the projected circle of the real helical coil. I will leave it up to the reader to perform this trigonometric exercise. The more segments in the polyline, the more accurate the model would represent the real helical coil.
However, EZNEC has a lower limit for the segment length which is proportional to the wavelength. In view of the two previous points, it is quite cumbersome to optimise a coil design using EZNEC.
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