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 ...

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197
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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 ...
85
votes
5answers
17k views

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 ...
68
votes
5answers
69k views

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 ...
48
votes
3answers
57k 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 ...
45
votes
11answers
132k views

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&...
44
votes
5answers
3k views

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 ...
39
votes
3answers
275k 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 ...
30
votes
6answers
10k 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?
28
votes
2answers
24k views

Why are brownouts so harmful?

I was reading http://superuser.com/questions/32840/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 ...
28
votes
4answers
102k 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 ...
24
votes
5answers
13k 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 ...
24
votes
3answers
3k views

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 ...
22
votes
4answers
2k 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 ...
21
votes
3answers
8k 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 ...
20
votes
7answers
16k 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 6 CPU cores for editing video and ...
20
votes
4answers
58k 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 ...
19
votes
5answers
45k 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.
18
votes
2answers
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, ...
18
votes
4answers
8k 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 ...
17
votes
6answers
12k 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-...
17
votes
3answers
13k 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 ...
16
votes
3answers
13k 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 ...
15
votes
4answers
2k 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 ...
15
votes
2answers
954 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 ...
15
votes
5answers
14k 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 ...
14
votes
4answers
20k 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 ...
13
votes
4answers
15k 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 ...
13
votes
5answers
11k 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 ...
12
votes
9answers
7k 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 ...
11
votes
2answers
358 views

My 386sx refuses to start in cold days

My old computer refuses to start in cold days. So, in really hot days (about 40ºC / 104ºF ) or even hotter, this PC usually starts, but in cold days, it wont. When the temperature is not in the "...
11
votes
6answers
757 views

are consumer grade power supplies designed to run 24/7?

I know many of you run machines at home 24/7 (servers, maybe even desktops) that run on standard consumer grade hardware/PSUs. Is this safe? Is there even a remote risk of fire hazard? I'm curious ...
10
votes
7answers
42k 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.
10
votes
2answers
38k 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, ...
10
votes
4answers
3k views

Does my 1000 watt 80gold+ (90% efficient) PSU pull 1111 watts, 1000 watts, or 900 watts from my wall receptacle at 100% load?

Does my 1000 watt 80gold+ (90% efficient) PSU pull 1111 watts, 1000 watts, or 900 watts from my wall receptacle at 100% load? When I plug my 200 watt video card into one of the PCIe power connectors.....
10
votes
2answers
2k views

What happens when laptops reach 100% charge?

I have been reading alot of mixed views on how Lithium Ion batteries work when it comes to laptops. I have the new dell xps 15, with an intel i7 cpu, 16gb ram, and a 512gb ssd. Is it bad for the ...
10
votes
4answers
160 views

Is there any computer parts that can be trashed safely (for the environment)?

I have some (non working) computer parts that I want to get rid of. I'm pretty sure most of computer hardware can't be put in the trash safely but I want to know if some of them can. (At the moment ...
10
votes
3answers
1k 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 ...
9
votes
3answers
3k views

Can I have too high a PSU power rating?

I have just ordered a 650 W PSU for my computer which previously had a 300 W, in order to install a more powerful graphics card. However, I didn't check whether anything would blow up ...
9
votes
4answers
16k views

How can I tell how healthy my PSU is?

Simple enough question, I have a hunch that my PSU isn't powerful enough based on a couple of clues: One of my screens flickers, and I read on a couple of websites that this could be caused by the ...
9
votes
5answers
23k views

Can you plug-in the battery while laptop is on AC only?

I'm using my laptop at home with battery removed and only connected to the AC power. However I'm lacking the mobility as my power cord is kinda short. Is it safe from electrical point of view to plug ...
9
votes
2answers
640 views

Where can I see what caused Windows to make the 'hardware disconnected' sound?

Whenever I switch my desk fan on or off, Windows makes a sound as if a USB device is being (dis)connected. I haven't been able to determine which device is being affected by the power spike, so I ...
8
votes
10answers
130k 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 ...
8
votes
6answers
31k views

How can I diagnose a faulty power supply?

I've got an older PC that freezes/blue-screens at non-reproducible times. I suspect that it's caused by a faulty power supply, mainly because I don't have any other idea. How can I diagnose this ...
8
votes
5answers
590 views

What are these? Are they broken?

Please excuse the poor image quality: What are the components that I've circled in red? The ones on the left look whole and solid. The ones on the right have cracked tops, and although this ...
8
votes
4answers
19k views

Why is the laptop charger thing (transformer) making a noise? [duplicate]

The laptop power cable consists of two cables with a transformer in the middle. The transformer is making a tiny noise while plugged in. I think it's normal... is it normal? What is it exactly?
8
votes
10answers
2k views

Can a UPS be too powerful?

Our old network admin bought the top range UPS a few months ago but never came around to setting it up and is no longer with the company. Now the old UPS broke down and needs to be replaced, but an ...
8
votes
5answers
11k views

Could I replace a stock PSU fan with a more quiet one?

I have a cheap 450W PSU with an exhaust fan at the rear. This fan, however, is very loud. Is it a good idea to replace the stock PSU fan with a quiet fan with similar airflow? The PSU fan is hard-...
8
votes
6answers
6k views

Is UPS necessary to have for a PC?

Can my computer components ( Monitor, Motherboard, RAM, HDD, CPU, SMPS) become damaged due to a sudden power flux. It's only needed to shut down Windows properly. Can I solve both Hardware and ...
8
votes
5answers
2k views

My power supply/motherboard nightmare

Last summer I bought a broken power supply (without knowing of course) and put it in my computer. Turning my box on made one of my cheaper HDDs catch fire (I believe a capacitor or resistor blew) and ...
8
votes
2answers
70k views

Can I safely use a PSU with an ATX 12v 4-pin for a board that has a EPS 12v 8-pin?

There's many similar questions to this, and because the answers vary depending on the setup, I want to ask for my friend's specific setup. He recently upgraded to a Core i5 gaming build, so he has ...