That inductance calculator is quite incorrect for all types of wiring one would consider. The return conductor is what defines the total external inductance of a wire. The internal inductance is 15 nH per foot, and completely independent of the conductor diameter.
A thinner conductor will indeed have higher external inductance, this due to the higher current density.
Externally, quite accurate. Internally, invarient.
You sound like another geek I know.
Well said..
Cheers, jn
Its just a link to his site Andrew, just use back space eh!
home page
Basicly they are the two of the most highly regarded people regarding shielding, EMC and grounding in the world, it only takes a bit of effort to register and you will be able to access a whole host of information covering what is being discussed.
At the end of the day, ALL the experts in the field recomend shielding connected at both ends for rf...
home page
Basicly they are the two of the most highly regarded people regarding shielding, EMC and grounding in the world, it only takes a bit of effort to register and you will be able to access a whole host of information covering what is being discussed.
At the end of the day, ALL the experts in the field recomend shielding connected at both ends for rf...
The best bet with H. Ott is get his book electromagnetic compatability engineering, chapter 3 covers grounding, chapter 6 covers shielding.
You dont require a registration code for the EMC club, just sign up.
Heres one article of interest from H. Ott site.
http://www.hottconsultants.com/pdf_files/ground.pdf
You dont require a registration code for the EMC club, just sign up.
Heres one article of interest from H. Ott site.
http://www.hottconsultants.com/pdf_files/ground.pdf
Yes. It was comparatively recently that I realised that the 'inductance' of an isolated piece of wire is not even well-defined, let alone calculable. I suppose it is because we can buy components with inductance labels on them, and there are formulae which give the contribution a piece of wire might make to a closed circuit (given certain assumptions).jneutron said:
Marce,
thanks for the OTT link.
I will read through and probably some others.
On reading the conclusion, I see I am one of the converted. I harp on about currents regularly, particularly what route the current returns by.
For every Flow there must be a Return, otherwise circuits cannot exist.
thanks for the OTT link.
I will read through and probably some others.
On reading the conclusion, I see I am one of the converted. I harp on about currents regularly, particularly what route the current returns by.
For every Flow there must be a Return, otherwise circuits cannot exist.
About 14 years back, I wrote code to calculate the inductance per foot for any arbitrary cross section of wire. I also wrote code to provide visualization, that's how I created my moniker. It was set to handle 16000 wires so that I could simulate any profile using a large matrix of individual conductors.
When I built the code to calculate the inductance of only 1 conductor with no return in a thin sectional length of wire, no matter how far out in space I went, the integrated field energy kept going up. Only makes sense, as doubling the distance of each thin shell doubled it's length, and the field falls as 1/r so halved. Each shell always had the same total energy..duh..
Yup. Very important to watch all the currents as well as all the current paths.
Cheers, jn
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