Ask A Scientist© Engineering Archive

Index Key:   ENG029
Author:      Allison Williams
Subject:     Electrical current
Text:        How does an electrical current work?

Response #:  1 of 2
Author:      jade hawk
Text:        This is a nice exercise in getting kids used to using a terminal, 
but NEWTON is not your school library's encyclopedia.  Current happens when 
electrons all move in one direction inside a wire.

Response #:  2 of 2
Author:      dipper
Text:        Actually, there are many volumes of books on the subject.  
Electrical current(s) are not only transmitted by wire, but also other 
mediums, such as air in a device called a wave guide when dealing with UHF 
(Ultra High Frequency electricity) or Microwave (even higher frequency).  The 
mechanics of electron (or hole) flow is and will continue to be a subject of 
considerable debate.  The effect of that current is what we all know about.  
As I said, there are volumes and volumes of books on the subject. In short, 
electrical current can flow only when there is a potential (commonly referred 
to as voltage) between two sources, and a path to equalize the potential.  
This potential can be created by many sources, including chemical energy, heat 
energy, and just about any force that can create substances that are charged 
more or less positively or negatively.  A battery, for example, is made of two 
or more chemicals or elements that are reacting to cause an electrical 
potential between two elements.  By connecting the two elements with a 
conductor of some type, or a "load," electrical current will flow in an 
attempt to equalize the differing electrical charges.  When the chemical 
reaction is complete, and the charges have been neutralized, no more 
electrical current can flow.  Sometimes the simplest questions can be the most 
difficult to answer.  Keep asking them.