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What is a power switch in a computer?

by Huyu 25 May 2023 0 Comments

Most modern computers switch on and off via power buttons. However, many desktop  power supplies are designed with switches. These switches turn on/off to control the power supply. If set in the off position, the computer won’t power on even when you press the power button. Learn more about the importance of power switches on desktop power supplies here.


Contact Apiele if you are looking for switches to replace the one on your desktop power supply. We have a collection of latching switches suitable for desktop power supplies.


What’s a desktop power supply switch?


A desktop power supply switch, aka a rocker switch, is a device that allows users to switch the power input on or off as necessary. It’s one of the basic types of electronic switches and helps control the power flow from the socket to the motherboard.


The switches toggle between two positions, on and off, usually indicated by a 1 and 0, respectively. When you activate the switch, it latches into the  ‘on’ position and maintains that state until you toggle it into the ‘off’ position. 


You could also use a momentary switch on the power supply or manually join the two wires connecting to the motherboard's power switch yourself. However, a latching switch is different because it maintains its position until pressed again. It’s safer than joining the wires yourself and doesn’t need holding down like a momentary switch.

The switch on the power supply usually serves as a secondary power control tool. However, primary on and off functions are via the momentary switch located on the front of a computer's case. Pressing the switch temporarily closes an electric circuit allowing power to flow and turn on the computer.


But you must switch on the latching switch on the desktop power supply first. Otherwise, there would be no power input to the system. You can use the power supply’s latching switch to completely cut off power to the desktop or turn it on if it has been switched off via the momentary power switch.


Uses of latching switches on desktop power supplies include


Performing power cycles


Some situations require completely cutting off the power supply to a  computer. Toggling the power switch to the ‘off’ position helps reset the desktop and clear residual power. This is recommended when removing or attaching devices, such as GPU, CPU, RAM, fans, etc., to the motherboard.


Indeed, it’s wise to cut off the desktop power supply whenever you want to inspect the inside of your machine.


Cutting off power when manually resetting BIOS


Shut down your PC and switch off its power supply anytime you want to update or reset BIOS. Computers have capacitors that retain charge. Switching off the power supply is a precautionary measure that helps clear off this residual power ensuring there is no electrical interference when manipulating jumpers or picking out the CMOS battery.


It also prevents the accidental triggering of certain configurations when making physical adjustments or temporarily removing certain components. Generally, performing the reset in a stable and controlled environment is wise to ensure a complete reset. Remove USB hubs, too, if you use any; some USB hubs are designed to store energy, so remove them for safety.


Cutting off the power supply before moving the desktop


It’s not wise to move a computer when it’s powered or still retaining standby power. Any vibrations during transportation can make components shift and touch, resulting in short circuits, data loss from hard drives, and even electrical shocks.

Always shut down the computer, switch off the power supply, and clear any residual power before relocating your computer.  You should also secure any loose components or cables inside the computer before moving it.




In addition to the primary power button at the front of desktops, some have power switches on their back panel, too. The primary power button on the front is typically connected to the motherboard and helps turn the computer on or off. On the other hand, the switch on the back panel is connected to the power supply and allows the user to control power input to the entire system.


The latching switches on power supplies add convenience and safety. Users can cut off the power quickly in times of emergency or when they simply need to perform troubleshooting and maintenance tasks without risks of short circuits or electric interference. Get in touch with the Apiele team for help selecting a power switch suitable for your desktop.

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