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.

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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 ...
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149 votes
6 answers
1.1m views

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 ...
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120 votes
6 answers
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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 ...
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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 ...
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65 votes
11 answers
89k views

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 ...
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61 votes
11 answers
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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&...
BIBD's user avatar
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58 votes
5 answers
106k views

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 ...
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45 votes
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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 ...
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42 votes
4 answers
225k views

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 ...
Dan's user avatar
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40 votes
3 answers
45k views

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 ...
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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 ...
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35 votes
6 answers
35k views

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?
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34 votes
2 answers
46k views

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 ...
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33 votes
6 answers
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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 ...
Peeyush Kushwaha's user avatar
31 votes
5 answers
11k views

Computer is frying all USB devices that are connected

My computer specs are as follows. The computer is almost 1 year old. It is custom built: Motherboard: ASUS h510m-a OS: Windows 11 PSU: EVGA 500BR In the past hour, I have connected multiple mice and ...
stickynotememo's user avatar
30 votes
5 answers
45k views

How to test a power supply?

My computer powered off the other day on its own, and now when I push the power button, nothing happens. My assumption would naturally be that the power supply is done (possibly well done) but is ...
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29 votes
4 answers
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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 ...
Enrique Moreno Tent's user avatar
27 votes
6 answers
51k views

Does a power supply draw only as much power as it needs?

I recently built a small mini-itx Intel ATOM-based Ubuntu home server. The case I choose is a small case but only a full size ATX power supply would fit it. I choose a mid-grade OCZ 500 watt modular ...
Jake Wilson's user avatar
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26 votes
4 answers
107k views

Laptop touchpad works incorrectly when on power supply

My original laptop adapter broke down, so I've bought a new one. It's a no-brand adapter from a Dutch internet shop. The power of the new adapter is slightly more than the old adapter, but in my ...
Ikke's user avatar
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25 votes
6 answers
90k views

Does laptop charger wastes electric current when not connected to the laptop?

Wonder if when I leave it connected to the outlet but not connected to the laptop, it still consumes electricity.
Oren A's user avatar
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25 votes
3 answers
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Why is a pin missing on 2x12 PSU cables?

I just noticed that finally entry model PSUs are now giving 2x12 power leads rather than needing to use a 2x10 in addition to a snap on 2x2. For the first time I actually looked at one and I thought I ...
William Hilsum's user avatar
24 votes
5 answers
19k views

How to connect an old motherboard with a 12 pins power connector?

On an old machine, the PSU died, and I attempted to change it. However, the power connector to the motherboard seems to be a weird 12 pin connector, and I can't seem to find any adapter with the ...
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24 votes
4 answers
5k views

Can unexpected power loss harm a Linux install?

I am developing an application on a Linux embedded board (runs Debian) e.g. Raspberry Pi, Beagle Board/Bone, or olimex. The boards works on an environment that the electricity is cut unexpectedly (it ...
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24 votes
4 answers
21k views

Can I run a computer using DC power?

I always thought that using a conventional UPS with a PC is highly inefficient. Power goes from AC -> DC -> AC in UPS and then AC -> DC in PC SMPS. Since PC works only with DC (12, 5 and 3 volts) It ...
Rajkumar S's user avatar
23 votes
4 answers
24k views

Can using the wrong power supply slow my computer down?

I have a Dell Studios XPS 1640, and it requires a 90W charger for use. I lost my power cable, so I'm now using a 65W charger. My computer has slowed down noticeably whenever it is charging. The ...
user3172050's user avatar
22 votes
3 answers
325k views

Do I need both the 8 pin and 4 pin cpu power plug for my MSI B450 Pro Carbon?

I have bought a new mainboard, an MSI B450 Gaming Pro Carbon, and to my surprise, it features 12 pins for the CPU power connection. My power supply, a Pure Power 10 BN274 600 Watt, only features 2 x ...
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21 votes
7 answers
52k views

Why does my PC successfully boot only when unplugged for more than a few minutes?

I have an HP Pavilion Elite desktop computer, model HPE-490t. I like it because it didn’t cost too much, boots itself from an SSD, came with 16 GB of RAM, and has six CPU cores for editing video ...
philg's user avatar
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20 votes
9 answers
137k views

What is the 6-pin power connector on an HP ProDesk?

I have an HP ProDesk 600 G1 desktop PC, and I'm upgrading it with a new graphics card and a new power supply. Now, the problem I'm having is that the motherboard in the PC doesn't have a standard 24-...
Squeazer's user avatar
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19 votes
5 answers
52k views

Stop Dell from throttling CPU with power adapter

My Dell laptop is experiencing the old problem of the power adapter failing to be recognized by the computer. I know for a fact it is just a break in the data cable in the line, because if I position ...
BarrowWight's user avatar
19 votes
2 answers
1k views

What kind of power port is this?

I'm planning on getting a new PSU and I was shopping online when I saw this thing. What kind of port is this? I've never seen it before, and I definitely can't find cables for this. For reference, ...
Kaz Wolfe's user avatar
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18 votes
3 answers
72k views

What is typical power consumption of 2.5" laptop external hard drive connected to USB socket?

What is the approximate power and current consumption of a 2.5" laptop external Hard Drive 7200RPM SATA (300Gb), connected to a laptop USB port as an external hard drive? I've heard that using a ...
Lexx Luxx's user avatar
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17 votes
5 answers
17k views

How can I guess if a USB cable will power my devices?

I've had problems with one long (4 meter) USB Mini-B to USB Type-A cable not being able to boot a 2.5'' external hard disc due to not supplying enough current. On top of that, the cable used a Type-A ...
Ricardo Sanchez-Saez's user avatar
16 votes
4 answers
53k views

Can PSU cause my PC to reboot?

I'm having an issue with my PC: It is rebooting sometimes, and I am suspecting the PSU, so I want to confirm a few things. It is a new PC and the first issues started occuring roughly one month after ...
skiwi's user avatar
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16 votes
4 answers
3k views

Buying A Computer "Case" Fan... Does It Always Run At 100% Unless Told Otherwise?

What happens if I do not plug it into the motherboard and it does not have a switch? I have seen fans before with an "off/low/high" switch that allows you to manually set their speed. I have seen ...
darkAsPitch's user avatar
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16 votes
9 answers
87k views

Workaround for Dell "Power supply not recognised" issue

I have a Dell Inspirion and the power supply port appears to be damaged. Basically when I plug it in I get a nice popup telling me that it couldn't detect that its a Dell power supply so it won't ...
Haedrian's user avatar
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15 votes
5 answers
16k views

How to get a second PSU to power only hard drives if the CPU and motherboard connectors are not used?

I would like to add more disks than my main PSU can handle, so I plugged them on another PSU (Corsair VS450) but it does not power them as CPU and motherboard connectors are not used. How can I force ...
Gaël Barbin's user avatar
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15 votes
2 answers
1k views

Identify AC Power Cord with rotated pins

Is this AC power cord connector a standard one? The pins seems to be rotated 90 degrees. This ATX power supply unit (Silverstone ST1500) did not come with the cord and I am hoping to be able to get ...
Nyxynyx's user avatar
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15 votes
3 answers
3k views

How to find out if Windows was running at a given time?

On Windows (7/8/10) is there anyway to find out if computer was running at a given time? (e.g. last night at 10 pm if the computer was running or turned off) thanks
ePezhman's user avatar
  • 273
15 votes
6 answers
106k views

How much power output can an 8-pin to 2x 6+2-pin connector output?

A common cable included in modern modular PSU's is the 8-pin to 2x 6+2 pin. However, based on reading (such as PCI-e Power - Does 6 + 2 Equal 8?) an 8-pin is effectively the same as a 6+2 pin. If that'...
WannabeCoder's user avatar
15 votes
3 answers
18k views

Notebook's Battery is not calibrated. Operates at 0% for an hour

My problem is that even if the battery percentage is 0 the notebook can stay on around an hour. I have disabled "critical battery action" on my operating systems to use more time my notebook. The ...
George Sofianos's user avatar
14 votes
10 answers
164k views

Why does my computer power off suddenly and without warning?

My computer is about 7 years old. Its has an Asus A7N266-VM motherboard and an AMD Athlon XP 2400+ CPU. My problem is that my computer suddenly and randomly switches off on its own. There is no blue ...
Felix's user avatar
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14 votes
7 answers
139k views

If my power supply is 700w, do I need a 700w UPS?

if my power supply is 700w, do I need a 700w UPS? I am running dual 20" dell LCD's, a i7 quad core system with a radion 4870 1gb video card, 2 hard drives.
user3183's user avatar
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14 votes
1 answer
4k views

Is it okay that part of the power jack is outside the device?

I have some devices whose DC adapter connector/jack is only partially plugged in. For example, my monitor has an AC to 180 W DC power supply. When connecting the transformer to the monitor, the DC ...
fatFeather's user avatar
14 votes
5 answers
16k views

Ungrounded laptop (Macbook Pro) buzzes in headphones, weird feeling when fingers brush lightly

I've got a nearly 3-year-old MacBook Pro 15" 2.16GHz (MacBookPro2,2). When I am not using the extended, grounded adapter for the power supply, just using the simple, two-prong plug, I can hear a ...
donut's user avatar
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14 votes
2 answers
3k views

Connecting switches between two buildings, each building has it own mains electrical supply

I have two buildings (A + B) each with their own mains electrical supply. The buildings are about 20m from one another. Between the two buildings are the Cat6 cables (one active and two spares). The ...
sam's user avatar
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14 votes
2 answers
114k views

How can I tell if an AC adapter is compatible with my laptop? [duplicate]

Possible Duplicate: charging laptop with a diffrent manufacture charger How can I tell if an AC adapter is compatible with my laptop? For example, does the voltage output have to bee the same, ...
Jim's user avatar
  • 359
14 votes
4 answers
69k views

PC shutting down after 30 minutes, even when on BIOS screen

I have a desktop PC that is just over a year old that I use daily for work. It's running Windows 8.1, has 16GB RAM and an i7 CPU. It has a 256GB Samsung 840 SSD (Windows + programs) along with a 1TB ...
Richard Ev's user avatar
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14 votes
4 answers
6k views

Is there a Internet PC Parts database? Like IMDB except it's about PC parts: motherboards, CPUs, Power supplies etc etc [closed]

I would love to have a central place where information about all PC parts are kept. Even better if the whole database can be downloaded as CSV and analysed using R or SAS.
xiaodai's user avatar
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13 votes
11 answers
16k views

Will leaving the laptop power brick connected to the power socket be dangerous?

My co-workers (who worked with the company longer than I have) loves to remove their laptop's power cord when they need to move around the office. I frown on this practice since they usually don't ...
MrValdez's user avatar
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13 votes
2 answers
12k views

Is it true that PC power supply screws are 'connected' to earthing/grounding pin of the power supply?

I was watching a YouTube video (I've provided link in the comments) where the user claims that sometimes when we don't have earthing done in our homes or you are using two pin plug in the socket, the ...
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