When it comes to the world of power supplies, there are only two contenders that we have right now. It is either we have the DC or the AC type of power supply. If we are talking about absolute necessity especially in our homes, then what needs to have is no other than the AC type of power supply. They are so needed since they help to regulate the amount of voltage that is being transferred to a certain device at home. Of course this is important. Without this regulation, devices that we have at home will surely blow because they cannot withstand the amount of current that is inappropriately being supplied into it. AC stands for alternate current. They are nonlinear and again, they are used most widely in the devices that we have at home.
DC power supply, on the other hand, is quite different than what we have for alternate current or the AC power supply. If you can remember, the AC type of power supply is of the nonlinear type, which means that the current can form sinusoid waves as it passes or travels. The Direct Current is different because it is of the linear type. This means that the flow or the current that travels stays in a direct line or linear form and does not form waves. The best application that we have for Direct Current or DC power supply is one in which there is application in stored form of energy. A perfect example for this would be the batteries and the fuel cells. Energy is stored in the form of chemical energy in these examples and when they are finally needed, they are then converted into a more useable energy in the form of electrical energy in which the device will need then.