In a computer, a power supply unit supplies power to various components by converting and regulating the mains power into required voltage. Certain components of your computer require accurate supply of power, as fluctuations can cause serious damage to them. Power Supply Unit (PSU) A computer power supply unit is made up of multiple pathways, which facilitate the power flow to various components as per the voltage requirements. The wattage, based on the maximum power which can be derived from the unit, acts as its most common specification. The total wattage delivered by the unit must be split across several pathways. A PSU for desktop computers normally ranges from around 400 watts to 1000 watts, but units which are capable of supplying power up to 2000 watts are also available. These units, which are very expensive, are most often used in workstations, computer servers, or home computers with multiple processors. There is a wide range of connectors which come standard on the power supply unit. They determine the capability of the computer and hence, it is important to ensure that the connectors included with the machine confirm to the requirements of the computer, or whether a reliable adapter is available to supply power to various components. Buying a PSU Other than wattage, you should also take connectors and application of the computer into consideration. You can either take the help of a professional, or use the services of some website that provides an online power supply calculator. To be on the safer side, add 30 percent to whatever result you get before finalizing the power requirement. It will ensure that you don't have to replace your power supply unit, when you add new components to your computer. Installation of the PSU The installation process can be a bit tricky and hence, should not be attempted by any individual who is not well-versed with computer hardware. The unit doesn't have any user serviceable components inside it, so there is no point in trying to open and repair it. The capacitors within unit, which are meant to store charge temporarily, can give you a high-voltage lethal shock, even when the unit is unplugged. Therefore, it is wise to leave the internal handling part to someone with expertise in hardware maintenance and repair. Most important aspect of the computer PSU is its use. You have to take the present usage as well as future usage into consideration when buying it. These units can be used for a long time and hence, choosing the right power supply with extra wattage is always a good idea. It won't just save a considerable sum of money, but will also ensure that you never face power crunch in the future.