Questions tagged [power-supply]

A power supply is an electronic device that supplies electric power to another device, such as a computer, monitor or printer. This is achieved by converting wall power (or mains power) to a lower voltage, and in most cases also from AC to DC. Most power supplies also provide protection from overload, power surges and other potentially problematic or hazardous conditions.

Power supplies for desktop computers are a standard design, but vary in output power. If you have more powered components (hard drives, optical drives, graphics cards, etc.) in your machine, you'll need a larger power supply. This is the main consideration when upgrading your computer.

Power supplies for laptop computers are usually specific to that make of laptop with each one potentially having a different output rating and connector. If you need to replace your power supply, you need to make sure you get one that's compatible:

See also

  • (uninterruptible power supply)
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Should laptops remain plugged in when their battery is 100% charged?

When your laptop's battery is 100% charged, should you leave it plugged in so any battery power doesn't get used, or will that cause overcharging, overheating, etc.? Should the laptop be unplugged when the battery level is 100%? I'm asking because…
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What is the power output of a USB port?

As the title says, what's the power output of a USB port? Is it a standard value, or it may change depending on manufacturer/model, and so on? If that value is not standard, how can one determine it?
Sekhemty
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Why do some AC adapters and power supplies generate a whining noise, and what can I do about it?

I have many different AC adapters and power supplies for a variety of devices, ranging from small 5V/1A USB chargers to laptop power adapters and desktop PSUs. However, I often hear a whining noise from some of these power supplies. This happens…
rishat
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Why are my games slower on battery power, even with the power plan set to High Performance?

My laptop is capable of running most games on high settings at decent frame rates. However, if the power cable gets unplugged while I'm playing, the game immediately starts slowing down, even if I'm using the High Performance power plan. Why does…
Egghead99
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What happens when hardware tries to draw more power than power supply can provide?

As far as I understand, computers don't always draw the same amount of power from the power supply all the time. There are times when hard drives are on standby and not using as much as when they're spinning and graphics cards save power when not…
user1306322
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Laptop power supplies, does current matter?

I have two laptops (same manufacture), with the same type of power connector. However, the power supplies/transformers are slightly different. The output on the first laptop's power supply is 15.6 V at 8.0 A. The output on the second laptop's…
BIBD
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How do you check how much power a USB port can deliver?

Some laptops have a special USB port that can deliver more power than the other ones. However it is not always easy to identify which one is the good one, nor how much power it can deliver. So is there a good way to figure it out? I'm open to any…
Peltier
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Pulling the plug out for 10 seconds

When calling support the other day he told me to reset my DSL modem by pulling out the power, leave it out for 10 seconds, and then plug it back in. This is something I have heard many times with different kinds of equipment. I have also heard it in…
Svish
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How to choose a UPS / calculate power for a new PC

Seven years ago a friend gave me a Liebert PowerSure 250 UPS and it has done well for whatever (home) PC and monitor I've plugged into it over the years. I've just ordered a new PC with the Intel core i7-920 and other nice specs for 3 HDDs, a nice…
Dan
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Why are there so many pins on a SATA power connector?

I was just looking at the power connector for a SATA optical drive and noticed that it had fifteen pins! I then marveled at the data connector next to it, which has a measly seven pins. I know that there are only physically three pins needed for the…
eleven81
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I plugged in a molex cable the wrong way and the power supply exploded. Did it kill my hard drive?

I bought a cheap kit allowing me to use a 3.5 SATA hard drive with a laptop, by plugging it in with USB. It still requires external power supply so I used an adapter that came with this kit but I plugged it the wrong way - the molex cable has four…
jy196
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Can touching any hardware inside a running PC be dangerous for you?

I'm curious, if all the hardware gets power from the PSU's DC power lines, which provide a max. voltage of 12V, can you get electrocuted by touching some of the hardware?
user81496
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Why are brownouts so harmful?

I was reading Is surge protection actually needed? and well I'd like to know why brownouts are so harmful. The explanation gave there is "the capacitors get above their rated voltage" But that makes no sense if the power coming into the PSU is less…
Earlz
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Do DC adapters consume energy when no device is drawing DC current?

Do DC adapters consume energy when no device is drawing DC current? Or… Can I leave my mobile (5-20 W) or laptop (40-60 W) chargers plugged in and switched on and hope they won’t draw current if my mobile or laptop isn’t plugged in to the…
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Is there a difference between 8-pin EPS12V and PCI-E connectors?

I was reading this article, and a question came to my mind. 8 pin EPS12V power cable 8 pin PCI Express power cable Besides the name and the color, these 2 connectors look the same. Is there a case where one should be used over the other? Is there…
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