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How electric current flow in a wire?

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2 Answers

Arvada,

It's difficult to give a short answer to your question, but I can leave out a whole bunch of details and give you a general idea.

Electrons are charged particles.  They have a negative charge.  An electron is normally part of an atom, so they can't easily be moved around without taking the whole atom with them.  But metals have a lot of electrons that aren't tied to their atoms very tightly and they can roam around within a piece of metal.  If we had a way to push them, they would flow as electric current.

To understand where the push comes from, you need to know that positive and negative charges attract each other.  If we could have a place where there are a bunch of extra electrons, that spot would have a significant negative charge.  Also, if we have another spot that is missing a bunch of electrons, it would have a positive charge. An electron that isn't tied tightly to an atom between these two places would be attracted to the side with the positive charge, and it would start to move.

The area between the positive and negative spots would have what's called an Electric Field caused by the charges there.  This field is measured in volts (technically volts per meter).  So voltage is the "pressure" that makes electrons move. Batteries and generators create the charge concentrations at their output terminals.  (How they do that is a different story.)  One terminal will be called "+" and the other "-", corresponding to positive and negative charges.  If you connect the battery's terminals to opposite ends of a piece or wire, that Electric Field follows the wire from positive to negative and all of the loose electrons in the wire start to move toward the positive end. Remember that the positive terminal of the battery is missing a bunch of electrons, so they flow into that terminal.  The negative terminal of the battery has a bunch of extra electrons, so it replaces the ones that went out the other end of the wire into the battery. The battery (or generator) soaks up the electrons going from the wire into its positive terminal and keeps replacing the electrons that go into the other end of the wire from the negative terminal.  The electrons moving through the wire are called the "electric current" which is measured in amperes, or "amps" for short.

That's about as simple as I can make the explanation.  Voltage is the pressure, and current is the number of electrons per second that go through the wire.  (It's a really, really big number!)  If you use water flowing through a hose as an analogy, the pressure (voltage) might be measured in pounds per square inch, and the current (amps) could be measured in gallons per minute.

I hope this helps you understand a little about electricity.

A wire functions as a conduit for electricity.  In order for electricity to flow through a wire a difference in charge must exist.  This difference in charge is measured in volts.  Since Electricity is the flow of electrons, electricity will flow from negative charge to a positive charge.