--- title: "What is a power supply unit (PSU)?" description: "What is a power supply unit (PSU)?" author: "Baishakhi Ghosh" published: 2023-10-06 updated: 2023-10-12 canonical: https://answers.mindstick.com/qa/102335/what-is-a-power-supply-unit-psu category: "hardware" tags: ["hard disk drives"] reading_time: 2 minutes --- # What is a power supply unit (PSU)? ## Answers ### Answer by Saumya Mishra **A [power supply](https://answers.mindstick.com/qa/102461/explain-the-role-of-a-computer-s-power-supply-cables-in-connectivity) unit (PSU) is a computer component that converts mains AC (alternating current) to low-voltage regulated DC (direct current) power for the internal [components](https://www.mindstick.com/blog/74096/understanding-the-role-of-some-integral-ac-components) of a computer. Modern personal** [**computer**](https://answers.mindstick.com/qa/102320/how-to-connect-a-printer-to-a-computer)**s 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](https://answers.mindstick.com/qa/94149/who-is-one-of-the-responsible-person-for-the-department-of-space-dos) for providing power to all of the components in [your computer](https://www.mindstick.com/articles/13023/choosing-the-best-power-cord-for-your-computer-a-layman-s-guide), including the motherboard, [CPU](https://answers.mindstick.com/qa/102316/what-is-a-cpu), [RAM](https://answers.mindstick.com/qa/102314/what-is-ram-and-why-is-it-important), GPU, storage, and fans. It is important to choose a PSU that is powerful enough to meet the [needs of your](https://www.mindstick.com/articles/13053/5-ways-in-which-your-mobile-app-will-serve-needs-of-your-business) computer. If you have a high-end [gaming computer](https://answers.mindstick.com/qa/109704/how-to-alternate-keyboard-shade-on-a-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](https://yourviews.mindstick.com/view/82588/4-ways-manufacturing-solutions-can-improve-your-organization-s-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. --- Original Source: https://answers.mindstick.com/qa/102335/what-is-a-power-supply-unit-psu Copyright © MindStick Software Pvt. Ltd. This Markdown version is provided for developers, AI systems, and offline reading.