how does current flow through an insulator?

Question

give me a link please

Answer 1

I can think of three ways, but there might be more.

First, few insulators are 100% perfect. A gigaohm barrier will look like an insulator for most purposes, but conduct a small current.

Second, a capacitor is an insulator (dielectric) connected to two electrodes. If you measure current external to the capacitor, it will appear that high frequency current passes through it, even if DC and low frequencies don't. What's happening internally is that, although charge carriers don't actually pass through the dielectric, the charge at one electrode creates an electric field that does pass through it. That field affects charge carriers (including electrons) on the far side of the dielectric.

The third mechanism is called tunneling, a quantum mechanical phenomenon. Electrons aren't truly point objects but clouds of probabilities - the electron's "location" is the center of the cloud, but it could actually be anywhere in that cloud. Modern computer chips use insulators about five atomic layers thick for gate isolation. This isn't quite right, but gives the idea: the "cloud" representing one electron is so wide that the edges of it are farther away than the thickess of the gate oxide. If the electron is close enough and the gate oxide thin enough, the electron is actually on both sides of the insulator at the same time. When there's an electric potential across the oxide, the weight of the cloud on each side of the insulator changes, and the electron can simply materialize on the other side of the insulator - it's called tunneling. Although it sounds spooky (and is), this "leakage current" accounts for a surprisingly large percentage of the 100 amps (give or take) that power a modern x86 processor.

Oh yeah - I forgot dielectric breakdown, when the voltage is so high that the electric field causes the insulating material to fail.

Answer 2

If you are in 5th grade, then perhaps the answer would be "No current flows through insulators by definition of an insulator"

But if you are in the real world, many of the other answers are correct, the current is so minimal. However, some insulators do have infinite resistance but only at low voltages. You need free electrons to pass electron current. But as you increase the voltage across the insulator at some point, the urge for the electrons to pass will force any material to give up it's electrons and pass them down.

So, no matter how good the insulator, if you have enough voltage, it will start to conduct. It's like money... if you have enough, you can buy anything!! (even youth).

Answer 3

if electrons are present then they are flowing smewhere and somehow - even in something that called an insulator. things are just relatively insulating. wood or plastic CONDUCTS poorly - however it still lets some electrons bleed through. ligtening will go through them quite easily - but as a LAST RESORT.

say you have two wires conducting current in the same direction from A to B. the vast majority of current flows on the outside of the copper wire, but some (very little flows near the center) some also flows through the plastic and still some flows through the plastic and joins with the other current of the other wire. this is known (usually in telecom as multipath effect or cross-talk).

electrons would prefer to flow on the exterior of a highly conductive path (ie copper wires) becuase the outside is the configuration where each electron is the furthest away from the others (remember electrons dont like each other b/c of their similar fields).

basicly if it has mass - it conduct electrity to some degree - its all greyscales.

Answer 4

It doesn't...hence its purpose.
(However, if you mean via the wire encased in the insulator, then the flow of electrons urged on by the Potential Difference (voltage) impeded by a resistance, will cause current to flow).

There are cases when PD is too high for the insulation, it breaks down and current will flow generally causing overheating, a short circuit and a blown fuse.

Answer 5

it does in two ways

I = V / R

even if the R is 1 Gig Ohm or 1 Tera Ohm
Ohms law still gives a current

The other way is tracking
if a defect is present or the insulator gets wet
then a surface spark develops, creates a plasma
and generally causes a burn mark ....which is the evidence of tracking

Once something has arced over (tracking has occurred)
it has failed as the damage made means that it can arc over easier and at a much lower voltage

the mark left is a burn mark and has carbon from the plasma and air

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Why ask for a LINK?

you can look for your own links if you don't like answers

just go to pictures of electricity stations pylons and transfomers that have arced over etc

Answer 6

If there is a potential, some current always flows.
The resistance of an insulator, (by definition), is
so high that the current is vanishingly small.

Answer 7

The insulator would have to have a level co carbon content, or it would have to be able to be charged with "+" or "-" electrons.

It also depends on tho more things. The Source Voltage and the Source Amperage.

Answer 8

Current does not flow through an insulator, which is why they are called insulators.

Answer 9

trick question...nothing flows thru an insulator.http://www.101science.com/transistor.htm