Thursday, January 22, 2015

electricity - What exactly is resistance and Ohm?


Ohm is defined as



"a resistance between two points of a conductor when a constant potential difference of 1.0 volt, applied to these points, produces in the conductor a current of 1.0 ampere, the conductor not being the seat of any electromotive force"



according to this wikipedia page. However, I still don't understand what exactly is resistance and ohm. Does resistance decrease the amount of electrons passing through a conductor per unit time or does it decrease the energy that a single electron carries or none of them? I know what Ohm law is and I also know the mathematical background of resistance but I can not understand the logic behind it.


For example, when we talk about a conductor that should be insulated by an electrical insulator we have to know how many ohms that is needed to determine the size of the insulator for a good insulation. But I would like to know how it is determined. Thus, I would be pleased if someone could explain the logical background of resistance and ohm. Thanks.




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