#24

AC vs. DC

Alternating Current

2/9/11

There are two major electronic currents used by people. They are called AC, alternating current, and DC, direct current. AC is the movement of electric charge periodically reverses direction. DC is the flow of electric charge is only in one direction. AC is very useful when kinetic energy needs to be transformed into electricity. It also ables electricity to be extended. For instance, a socket that you can see in any rooms is kind of like AC. DC, however, is used when chemical energy is transformed into electric energy. You can imagine of batteries or fuel cell, which are portable. Nikola Tesla invented AC, and DC was invented by Thomas Alva Edison. In the old days, the US was considering whether or not they should use DC. They had a huge debate about it and after all, AC won. So USA used AC as a whole.

             AC is usually provided in buildings. In Korea, they use 60Hz, which means in a second, current changes 60 times. If you see AC on a graph, the graph should show a wavy line.

<DC, on the other hand, shows a straight line on a graph>

             In the old days, as I said before, used AC. But nowadays, we use both AC and DC, because the technology of handling electricity has improved enough to find a way to convert AC to DC or DC to AC, by placing ‘diode’. However, this process wastes a lot of energy. Fill the heat from back of a computer or a TV? That is the wasted energy during the process. There are a lot of home appliances that are semi conductive. These semi-conductive machines mostly use DC power. That means that AC power that goes into the machines need to be changed into DC in order to get the machines going. That process, as I stated, wastes a ton of energy. Some people nowadays use solar energy, thinking they are saving energy. Despite all those effort people put into installing and actually using the solar panel, they still are wasting energy. Solar panels just basically store the electricity they gained by solar energy into a huge ‘battery’, which equals to DC. This again leads to the same energy-wasting-process. As a conclusion, people are just wasting a lot of energy whether it is AC or DC. We, as a whole, need to find smarter way of using Ac or DC, and fast.