Why a Simple straight wire is an INDUCTOR ??

Why and How a Simple straight wire is considered(equivalent circuit) as an Inductor at Higher Frequencies ??
for example in a PCB we consider a long trace to have large inductance although it's straight.
if anyone knows why it happens or actual physics behind it....please let me know....

Thank you..

Hello my friend!
It is simple . Each wire (When has current) has a field ( electrical ) . ( like an inductor) . L depends on the distance of your wire , and some other things .
And it is an inductor at all of the frequencies , but at high frequencies , it has sensible effect . ( consider that it's inductance is about 2nH . at high frequencies , it is as an RFC. ( such as 15GHZ)
Best Wishes
Goldsmith

---------- Post added at 13:18 ---------- Previous post was at 13:15 ----------

When you have an inductor with some turns , in fact you have a wire , but with winding you can do summing , between fields .

Inductance is the phenomenon where a changing magnetic field causes (induces) an electric current
to flow in a wire. Self inductance occurs when a changing magnetic field caused by a current in turn
causes another current to flow in the opposite direction and so partly cancels out the original current.
Currents add algebraically, so the total current would be the original minus the self induced current.
We dont actually measure these two currents individually however, we only measure the total current.

So we have induction, which is a change in magnetic field producing a current in a wire, and self induction
where a change in current produces a change in magnetic field which in turn produces another current
in the opposite direction and so cancels out some of the original current which reduces the total
current flow at that point in time. An inductor exhibits this behavior so we measure the inductance
and this is what is called the self inductance. It's in units of Henries.

There are a couple of equations if you would like to try to work out some examples.
The first and simplest one for inductance is:

V=L*di/dt

where
V is the voltage across the coil,
di is the change in current through the coil,
dt is the change in time between points we are looking at, and
L is the self inductance we talked about above.

The above is sometimes estimated by calling di and dt "delta i" and "delta t" where these two are relatively
small changes in the variables i and t.
For example, we might look at this equation at two points in time at t=10.0us and t=10.1us, so dt=0.1us here,
and measure current levels i=1.000 amps and i=1.001 amps, where di would be 0.001 amps here.
Knowing the self inductance L for that coil, we could then calculate V.


So, the changing magnetic field produces a current in the opposite direction which reduces the current
in the original direction.
It doesnt matter if there are turns or just straight wire because a straight wire has a surrounding
changing magnetic field too.
If the magnetic field stop changing, so does the reverse current effect.
That's why we have to use a changing quantity to measure the inductance of a physical inductor or wire.
The higher the self inductance, the more the changing field reduces the original current.
We only measure the net effect when we measure the current so we see it as a reduction of current
as compared to a wire that had no inductance at all.

Inductance is when a magnetic field 'induces' a current in a wire.
Self inductance is when the very device that produced the magnetic field induces
another current within itself that reduces the original current.

(electro-tech-online.com/general-electronics-chat/118906)

Calculating straight wire inductance.....

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**broken link removed**

Thanks dude for this...

but can we prove it mathematically.....that a small wire segment acts like an Inductor.

nikhilsigma said:

Thanks dude for this...

but can we prove it mathematically.....that a small wire segment acts like an Inductor.

Click to expand...

Inductance of a Straight Wire: A Calculator

Straight Wire Inductor Calculator

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Just use Google search field to googling Internet.

Basically, self inductance is defined and can be measured only for closed conductor loops. That's also true for a straight wire, the value will change depending on the return path.

A simple geometry that clarifies this relation is the well known parallel wire transmission line. The inductance per length unit is a function of ln(d/r) (conductor radius and wire distance). The value doesn't converge for d -> ∞.

but can we prove it mathematically.....that a small wire segment acts like an Inductor.

Click to expand...

There is a natural phenomena that the changing current flow in a conductor produces an opposite current in that conductor (in short words, want detail study the Inductance), this opposing current reduces the flow a bit in original direction, this fact is known as INDUCTANCE. So any conductor carrying current will have inductance. Specially on High Frequencies this effect increases (the rapid change will induce more opposing current)
For different conductor shapes look here:
Inductance Calculator