What Does a Computer Power Supply Actually Do?
What is the purpose of your computer power supply and why is it so important? The power supply in your computer is responsible for converting AC power from an outlet to DC current that your computer can actually use. The power supply is rated by the maximum wattage output it is capable of producing. To put things in perspective, the average laptop power supply might have an output of 200 or 300 Watts. The average desktop computer might have an output of 500 to 700 Watts. Most power supply units will automatically flow any required wattage up to their maximum rating. Typically, the motherboard determines power allocation for the internal computer components. Some other internal components such as fans or graphics cards may be connected directly to the power supply. This method is generally reserved for higher power consuming components, as this method bypasses the motherboard completely.
The power supply is usually easily identifiable as it is likely the metal box in the corner with the power cable plugged directly into it. You may note the colored wiring to and from the power supply. When you push the power button on your computer, this sends a message to the motherboard to turn on the power supply, and supplies the other necessary components with power.
The power supply is generally regarded as a cheap component; therefore they are not usually repaired, simply replaced should they ever break. Over the years power supplies and gotten greener and are now around 70% efficient. Anything a power supply doesn’t convert to power is thrown off as heat. Heat is waste, so the less heat you have, the greener your power supply. In other words if your power supply is consuming 700 Watts however only supplying 550 Watts total to your components, the missing 150 Watts is lost as heat. In this scenario, our power supply is over 78% efficient which is slightly above average. Generally speaking, the more expensive the power supply, the more efficient it is. For example, some power supplies designed for large servers (running 24 hours a day) can be over 90% efficient. These aren’t cheap power supplies however, and with a normal desktop computer, the power supply isn’t likely to produce an excess of heat.
The average power supply has a lifespan rating of around 100,000 hours. This corresponds to around 10 years of continuous operation. However; as with any product individual mileage may vary, but your power supply should still outlast your other computer components. If for some reason it doesn’t however, luckily they are pretty cheap.