by David Kopczyk

Created on: February 05, 2010

The battle for dominance between alternating current (AC)  and direct current (DC) may never come to a close, as they both are important in today's electronic-fueled society.

A short explanation on electricity is necessary to understand the more important nuances of alternating and direct current.  There are three keywords that are most important: voltage, amperage, and resistance.  Voltage is how much "push" the electricity has.  Amperage, also called amp for short, is a way of describing how much electricity is flowing.  Resistance can then be considered an opposing force to voltage, as it means the electricity has to "push" past the resistance to continue.  The easiest way to visualize these three topics is with that of water going through a pipe. Voltage can be visualized as the size of the pipe.  As the size of the pipe increases, lots of water can be pushed through it.  Amperage is how fast the water is flowing through the pipe.  Resistance can be likened to putting your finger over the pipe.  There is little water coming out, but it comes out much faster.  The less water coming out likens to less voltage and the higher speed of the water likens to a higher amperage.

So far it's simple, right? However, there are a few caveats and addendums. Unlike water, electricity will not flow in one direction.  Batteries and other energy sources generate electricity by making electrons move from a negative to a positive pole.  When the electrons from one side of a battery want to go to the other side, they must find a path there. If the path is broken, they cannot move and no electricity flows through a circuit.  This is how most lightbulbs function; the switch can break or connect the path, which then allows electricity to flow.

The above example was one of direct current.  You will find this inside electronic devices for the most part.  However, alternating current is used for almost everything else, as it has some advantages over DC.

Alternating current makes use of some properties of the electron.  Electrons move at almost the speed of light, which means that electricity can travel long distances in a short amount of time.  So theory of alternating current is that the current will flow one way, and then switch and flow the other way.  It's that simple.  Exactly like DC, except that instead of electricity flowing one way, it flip flops. 

There are advantages to using AC and DC in different scenarios, such as using DC in electronics and AC in power lines and for household wiring.  For more information on AC and DC, check out the following links:

Circuits: AC

Circuits: DC

Learn more about this author, David Kopczyk.
Click here to send this author comments or questions.