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Direction of elecrical current

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901310.  Fri Apr 13, 2012 1:51 am Reply with quote

Sorry to nitpick, but I feel I must point out that on page 347 it is stated:
"...this alternating current had to be converted into 'direct' current, similar to the electricity produced by a battery, where the electrons all flow in one direction, from the positive to the negative terminal."

This is not true. The electrons (being negatively charged) flow from the negative to the positive terminal. The notion of an electric current was developed before this property of the electron was known, which is why the direction of current is opposite that of the electons.

That's got to be worth a couple of points!

Thank you.

901478.  Fri Apr 13, 2012 10:32 am Reply with quote

Welcome to the QI forums, Bill, and have a heap of points! I cannot dispute your analysis, mainly because I am Mrs Thick when it comes to this kind of thing, but I am fairly sure those on this forum who know more than I do will pile in with quibbles or commendations.

901494.  Fri Apr 13, 2012 11:13 am Reply with quote

Direction of electrical current is a real can of worms. Chemists will almost universally agree that it is the flow of electrons down a concentration gradient. Physicists and electronic engineers will wax lyrical about positive holes and such like. The point is that conventional current is called that because it is the accepted direction of current by convention.

901530.  Fri Apr 13, 2012 12:39 pm Reply with quote

A hole is a mathematical device to represent the absence of an electron and not a physical entity (you may argue that an electron is not a physical entity, given its wave/particle duality).

But the point I was making was that electrons in a battery flow from the cathode to the anode (negative to positive).

Last edited by BillWestgarth on Sat Apr 14, 2012 5:17 am; edited 1 time in total

901536.  Fri Apr 13, 2012 12:53 pm Reply with quote

I'm a chemist Bill and I agree with you, but I'm merely pointing out the counter argument that you are aware of so I will not repeat.

901600.  Fri Apr 13, 2012 6:55 pm Reply with quote

The other nits to pick are that electrons don't flow and not all in one direction.

901601.  Fri Apr 13, 2012 7:11 pm Reply with quote

Drift would be a better description.


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