A power supply unit (PSU) is a computer component that converts mains AC (alternating current) to low-voltage regulated DC (direct current) power for the internal components of a computer. Modern personal computers universally use switched-mode power supplies. Some power supplies have a manual switch for selecting input voltage, while others automatically adapt to the main voltage.

• The PSU is responsible for providing power to all of the components in your computer, including the motherboard, CPU, RAM, GPU, storage, and fans. It is important to choose a PSU that is powerful enough to meet the needs of your computer. If you have a high-end gaming computer, for example, you will need a more powerful PSU than if you have a basic laptop.

Here are some of the factors to consider when choosing a PSU:

• Wattage: The wattage of the PSU is the amount of power that it can provide. Choose a PSU that has a wattage that is higher than the total wattage of all of the components in your computer.
• Efficiency: The efficiency of the PSU is a measure of how much power it wastes. A more efficient PSU will waste less power and save you money on your electricity bill.
• Form factor: The form factor of the PSU is the size and shape of the unit. Make sure that you choose a PSU that is compatible with your computer case.
• Modularity: Modular PSUs allow you to disconnect the cables that you are not using. This can make it easier to manage the cables in your computer case.