On 7/18/22 10:10 AM, Marc et Nicole Feuggelen-Verbeck wrote:
What you say is correct but that is nitpicking : The value of an inductor does not change with increasing or decreasing frequency . 100?H now equals 100?H just as 100KOhm is equal to 100KOhm .
If not , the laws of physics must be rewritten . F=1/2(pi)(sqrt(LC))
An inductor is *a passive electronic component that stores energy in the form of a magnetic field*. In its simplest form, an inductor consists of a wire loop or coil. The inductance is directly proportional to the number of turns in the coil , the used materials and the envirement but not the frequency.
ideal inductors have zero diameter conductors with zero resistance, and the inductance is
proportional (approximately) to *square* of turns, (if all the turns are equally well magnetically coupled)
The *inductance* of a real inductor most certainly changes with frequency (as captured in standard works like those of Rosa and Grover)
for a variety of reasons - mostly that with finite sized conductors, the current is not distributed evenly, and that distribution depends on the frequency.
There is also an issue of "effective impedance" in that inductance can be partly cancelled by capacitance (in the worst case it completely cancels at self resonance).
End of story
Marco
Op 18/07/2022 om 15:42 schreef Jim Lux:
On 7/18/22 2:20 AM, Marc et Nicole Feuggelen-Verbeck wrote:
The value of an inductor is a given and depends on several factors, but CERTAINLY NOT on the frequency
An ideal inductor, perhaps, but any sort of practical real inductor with parasitic C between turns and the surroundings varies with frequency. The loss also changes with frequency due to skin depth changes (although that's a small effect).
There's also a small inductance change effect due to different distribution of current in windings due to skin effect.
Finally, if the inductor is on a core, pretty much every core material has frequency dependent properties.
