Questions tagged [atx]

ATX is the standard for PC power supplies. It has +3.3 V, +5 V, and +12 V. They share a common ground. It has a PS_ON# signal which needs to be grounded to turn it on. Don't open power supplies that run on line voltage (AC). They have dangerous voltages and currents inside

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25
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1answer
2k views

What is this transformer-like component, and why is it not really connected?

Recently, a power surge took out a few components in my PC's ATX power supply. While repairing (I hope), one component in the power drew my attention. I'm an electronics engineer, but I'm confused ...
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5answers
45k views

24V 3A from ATX power supply?

I am looking for a cheap way to get +24V DC max 3A from computer power supply. I prefer easy soldering solution like DIP, and standard components that do not need to be purchased over internet. Any ...
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4answers
8k views

Why is there a -12V rail for ATX [duplicate]

The ATX specification includes a -12V (and an optional -5V) rail on the main power connector. What are these negative voltage rail used for on the connected circuits?
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1answer
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How can I use an ATX power supply for my own experiments?

I've been trying to turn on an ATX power supply I had lying around, and I plan to use it for some electronic experiments. Note: I don't want to have to open up the PSU for any reason. I've tried ...
11
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2answers
17k views

Can an ATX PSU power a USB port directly?

I'm going to build a benchtop PSU from an ATX PSU, and I would like to add a USB charging port on it. It should be able to power an Arduino or charge my (non-Apple) phone. (I know Apple devices ...
8
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6answers
3k views

Why are DC-DC ATX converters so big?

I watched an interesting video in which the caster reverse engineers a modern 850W computer PSU. From this teardown one can see that 90% of the bulk of the PSU is devoted to synchronous conversion of ...
7
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2answers
6k views

Fixing an ATX PSU

I have an 800W ATX power supply given to me by a friend because it doesn't work any more. It's quite a beast and would set me back a considerable amount new, so I'd like to see if I can fix it. Well, ...
7
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2answers
2k views

What's all this “rails” nonsense on a computer power supply?

This is in danger of becoming a computer question, but I've always wondered why do computer power supplies have so many 12V "rails". I have a 800W dead supply with four 12V 16A "rails", but internally,...
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3answers
21k views

Using PWR_OK to Activate an ATX Power Supply Automatically

Okay so, I have an ATX PSU that isn't connected to a motherboard, and I'm currently using the simple paper-clip trick to ground PS_On in order to trick the PSU into ...
6
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3answers
3k views

Combine multiple ATX power supplies?

For several different projects, I need high current DC power (25-50 Amps). The first project needs roughly 50 Amps at 12 volts, which isn't something one ATX can provide on its own (at least I don't ...
6
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1answer
6k views

LED specs for atx power on status

Most ATX motherboards have those same pins for 'interfacing' with the computer case... depending on the manufacturer they vary on position (hence loose wires at the case end) but never function. So i ...
5
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1answer
2k views

Is it safe? 9v from 12 to 3.3 on ATX PSU

I've an ATX PSU that I've modified to run without a motherboard, to power the many (6 or so) low amperage 12v and 5v devices at my workspace, to reduce # of power adapters plugged in and to provide ...
5
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2answers
9k views

Voltage Regulators in Computer Power Supply?

I have a damaged ATX 230WCE power supply unit and wondered if I could find 12V, 5V, and 3.3V Voltage regulators inside. I tried looking in another unknown model psu and only found transistors and ...
5
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1answer
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What is the capacity of capacitors in this power supply circuit?

Imagine the following circuit with two capacitors and diodes acting as passive PFC. My question is what is the capacity of these two capacitors? I mean compared to a circuit with just a single ...
5
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2answers
642 views

Use ATX power source to power Raspberry Pi

I'm setting up several Raspberry Pi's and Arduinos connected together, and I'm looking for a way to power them. Would it be possible to adapt an ATX stock power source with female USB plugs using the ...
5
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1answer
5k views

ATX PSU 5VSB + 5V

Is it possible to connect both the 5VSB and 5V pins of an ATX PSU to provide +5V? I would like to be able to initially boot using the 5VSB, which is always enabled. Once I've completed setup I would ...
4
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5answers
29k views

Does an ATX PSU's PS_ON Signal Require Resistance

As the title suggests; when connecting the PS_On signal directly to ground in order to switch on an ATX PSU, is there a required amount of resistance? - To try to clarify my particular problem; I ...
4
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2answers
9k views

How to make my own atx power switch?

I'm assembling a new computer from components. It's something I've done quite a few times, but now I would like to skip the case. Except for some structural integrity and LEDs, the only technical ...
4
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2answers
4k views

ATX power supply max current 12V P8 connector

I'm using a ATX power supply as a unit for my project. The power supply is of the type "be-quiet" straight-power E8 480W with cable management. I cannot figure out how much current can I get from the ...
4
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1answer
215 views

Increasing 12V Rail current on power supply for mobile computing

I am building a miro-itx slimline pc for my mobile home that is powered by solar. I have selected a GPU with a rated TDP of 120 Watts and a CPU with a TDP of 53 Watts.I purchased a DC-DC buck ...
4
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2answers
8k views

ATX power supply front-end: How does this work?

I've been trying to educate myself on general power supply operation and stumbled across several schematics for ATX power supplies. In general I understand how a SMPS operates, and an ATX PS is just ...
3
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4answers
1k views

Type of Header for Motherboard PWR Switch

I am trying to make my own 2-position connector cable to connect a Rasberry to the PWR_SW's PWR and ...
3
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2answers
3k views

Does an ATX power supply have any isolated outputs?

I am working on an application that requires isolated power inputs. Wondering if the standard ATX PSU has any isolated outputs? Why are we having multiple ground pins on the Connector?
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2answers
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Can I get 24V from ATX PSU using 12V and -12V cables?

ATX PSU's have one -12V cable, and a few 12V yellow ones. Could I power up a 24V device by connecting 12V to + on the device and -12V on -?
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4answers
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Is the flatness of DC output of a typical ATX power supply unit worse than a power adapter?

I converted an ATX power supply unit (Seasonic, 330W) into a standalone power adopter (by adding load, etc.), to which I connect multiple things. When I plugin a computer and a monitor each to a 12VDC ...
3
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3answers
2k views

ATX Computer PSU: OK to connect loads between positive rails, e.g. +12v to +5v

I have looked, but haven't find an answer. Are ATX computer PSUs capable of having a load connected between their positive rails, so that for example, current would flow from a 12v rail to a 5v rail? ...
3
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5answers
40k views

How can I power my 6-pin PCI Express card without using an ATX power supply?

One of my older computers has a 365-watt power supply that, for various reasons, cannot be replaced with a new power supply. I would like to upgrade the graphics card in that computer, but all the ...
3
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1answer
1k views

ATX power supply specification question

I read the ATX power supply design guide, and I have a question related to the PWR_OK line specifications. In "Table 21. PWR_OK Signal Characteristics" I saw the following: "Logic level high - ...
3
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2answers
9k views

ATX Power supply 5V rail Peak Current

We have setup, where 16-24, 2.5" Drives will be arranged in mobile racks of( 8 or 12 each). We are selecting ATX SMPS to satisfy these needs. We need to power these drives with a ATX Power Supply. ...
3
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2answers
5k views

Why have atx power supplies need selector voltage?

I am studying various ATX power supplies schematics and don't understand the need of the voltage selector as switching power supplies work at range of voltages. In most schematics i see the 110V line ...
2
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2answers
2k views

Convert the input of an ATX power supply from 110 V AC to 11-14 V DC

I was just wondering if it is possible to convert an old ATX power supply for my server. It feeds with 110 V AC from the grid, but I want to operate my mainboard directly from the solar battery, which ...
2
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4answers
4k views

How to use a NPN-Transistor to get status LEDs for an ATX power supply?

There are many instructions "How to Convert a Computer ATX Power Supply to a Lab Power Supply". Often they suggest they suggest to place to staus LEDs to indicate it the power supply is turned on or ...
2
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5answers
3k views

ATX power supply minimum load

I know this is a commonly asked question but most of the answers I got are more than 5 years ago. So basically, my friend found a ATX power supply and was going to give it to me. Since I already have ...
2
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1answer
2k views

Why do graphics card power cables (PCIe, etc) use more than two wires?

High-end graphics cards need more power than can be delivered through the PCI slot. One option would have been to deliver the extra power using a 4-pin Molex or SATA power connector, but recent ...
2
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1answer
1k views

Magic smoke released from DIY PSU… but why?

I'm starting to learn what I can about electronics, and recently decided to follow this (and similar) guides to building a bench power supply out of an ATX PSU: http://www.instructables.com/id/Convert-...
2
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1answer
126 views

Embedded PS vs ATX PS, can they used in place of each other?

The embedded power supply in my machine has gotten damaged/weak, It is used for powering only the Embedded Computer/Controller on the Machine. The Embedded Power Supply looks something like this. http:...
2
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1answer
738 views

ATX - replace passive PFC to active

I have some ATX PSU with passive PFC (huge coil with capacitor). I also have some active PFC from other ATX that based on L6561 IC. This psu will handle odroid xu4 board and few led strips based on ...
2
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1answer
1k views

Turn on 12v car amplifier with ATX POWER_GOOD?

Does anyone know how to turn on a 12v subwoofer amplifier, using the ATX power supply control wire for POWER_GOOD? I am using an Azza model PSAZ-1000A14S, 1000 watt, single 12v rail, computer power ...
2
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2answers
903 views

Can I use a 12V 70A source to convert/boost to 24V 5A supply?

I have a self built custom made computer that is using a Ultra X3 1000 watt power supply. Over the years I have been reducing the power needs by adopting more energy efficient hardware. My computer is ...
2
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1answer
2k views

Power ATX motherboard from JAMMA

I have some arcade cabinets with computers in them, and I'm using a regular PC PSU for them, which sucks because it takes up so much space. I know there are pico-psus on the market, but I don't ...
2
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1answer
589 views

Different voltage rails output filter does share same core

I am reviewing circuit diagrams of ATX power supplies. I have noticed this in almost all different designs of ATX power supplies. Different voltage power rails output filter share a one core [ toroid ]...
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0answers
85 views

ATX power supply doesn't cut the current after being turned off

I made a power supply for my electronic projects using a ATX power supply of a older computer and used a button connecting the black and green wires to turn it on/off. I noticed that sometimes when I ...
2
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0answers
691 views

Advanced ATX Power Supply Modifications

I know there are multiple tutorials and questions regarding converting an ATX power supply, new or old, to a benchtop power supply for projects. I'm fully aware of how to make the basic conversion to ...
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4answers
8k views

Can 12V car windshield wiper motor be powered using PC power supply?

As title says, can 12V car wiper motor be powered using PC power supply? According to amperage of typical car wiper motor I would say yes, but I want to check :) Thanks in advance
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2answers
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Dangers of Old ATX Power Supplies?

I was tearing open an old ATX power supply from one of my old computers today, because it was making a funny high-pitched wining noise. I noted that several of the components within were starting ...
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3answers
2k views

How safe is parallel wiring two ATX PSUs, if they weren't explicitly sold as dual PSUs?

Pages such as this discuss wiring ATX PSUs in parallel, in what seems to be a sensible manner, with links to various projects showing details. Companies with a decent reputation for ATX PSUs, sell ...
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2answers
2k views

What is the correct replacement for this mosfet?

I'm trying to repair a broken DC-ATX power supply that I have. After a bit of searching for faults I believe I have tracked the problem down to one of the MOSFETs. I would like to try replace this ...
1
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1answer
21k views

Charging battery using computer power supply?

I have new 600W ATX computer power supply unit. I have wired green and black together to make power supply turn on when plugged in. I wanted to charge my 12VDC empty battery, without dealing damage to ...
1
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2answers
1k views

Galvanic isolation between AC input and DC output?

An ATX motherboard is grounded to an ATX PSU thru the ground wires, from the 24-pin power connector to the PSU. Is there (inside the ATX PSU) galvanic isolation between the DC output and the AC ...
1
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1answer
129 views

How come PC/laptop power suppliers have much higher wattages per physical size than laboratory switching power suppliers?

This 2.2 kg 1000W BeQuiet BN213 ATX power supply is able to provide 12V 83A (no typo. Eighty-three.), which is around 1000 W. This huge PS900W (60V15A 30V30A 15V60A) bench power supply weighs 5 kg ...