This might sound like a stupid question, maybe even so obvious that I can't find the answer anywhere else, but could someone please shed light on why inductors don't short out?

With basically all of the inductors that I've seen, the wire coils touch.. a lot. Why doesn't the electron flow just take the "path of least resistance" and go straight from the input lead to the output lead?

To illustrate, my understanding of how electricity flows through a conductor is as follows (please excuse the dodgy looking MS Paint overlay):

(Presumed) actual inductor behaviour

Since the wires are touching, I'm wondering why it doesn't go like this: Logical inductor short circuit

The only explanation that I could think of is that the silver-coloured contacts at the ends (somewhat covered by my drawing) are actually elemental silver, and the wires are only coated in copper. This seems like the only explanation, because according to www.tibtech.com/conductivity.php and chemistry.about.com/od/moleculescompounds/a/Table-Of-Electrical-Resistivity-And-Conductivity.htm, the only thing with less electrical resistance than copper is silver. Presumably the difference is sufficient to force the current to run the entire way around the coil and not just short through the copper.

If anyone could shed light on this, that would be great - thanks :)

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    \$\begingroup\$ The wires are solid copper which conducts very well. However they are coated in tough but transparent varnish, which is a good insulator (unless damaged, or deliberately scraped off, or overheated). \$\endgroup\$ – user_1818839 Jan 21 '16 at 0:36
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    \$\begingroup\$ To check what @Brian said, set multimeter to continuity and touch probes - without applying too much force - on different sides of the same turn. The meter should show no continuity because of the varnish. \$\endgroup\$ – Nick Alexeev Jan 21 '16 at 1:01

Enameled wire, or magnet wire, just like larger gauge wire, has an insulating jacket. Enameled wire uses enamel, a paint like liquid that hardens into a solid, instead of a plastic sheath like 22 awg telephone wire or anything similar. It's super thin, and a PITA to scrape or burn off completely.

From Wikipedia: Cross-sectional view of AWG33 magnet wire taken using a scanning electron microscope: enter image description here

So when wrapped together, there is insulation preventing the wire from shorting out. This is why you have to be careful in winding a transformer/inductor/air core that you don't nick the wire, or it will short out.


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