Do PC ATX Power Supplies Output AC or DC Current and How to Identify Cable Voltages?

Question

I have a question about the power supply from an old PC. Do computer power supplies provide alternating or direct current? And how to recognize which cables provide which voltages? If such/a similar post has already appeared, I apologize in advance and in such a case please provide a supporting...

zybex · Accepted Answer

It`s definitely AT. It should also have a power switch or cables going out to it. These two 6-pin connectors were plugged into the motherboard. In addition, there should be 4-pin connectors with +5V and +12V power supply, which I wrote about earlier. In 6-pin connectors, black is ground, red is +5V, white -5V, yellow +12V, blue -12V (I just checked it on a similar power supply). Here is a sketch from a certain website. Why complicate your life when you can easily buy a 12V AC transformer?

zybex · Accepted Answer

You connect the bulb to ground (GND) and +12V. Add the negative voltage you mentioned and you would have 24V. The bulb would probably burn out. This is actually not a symmetrical power supply, because +12V voltage has high efficiency, and -12V has low efficiency.

zybex · Answer

They only provide direct current. In a typical power supply that has connectors for powering hard drives and drives, the red wires are +5V and the yellow wires are +12V. Black is mass. However, it is best (if you may have a different type) to measure individual output voltages with a meter.
I know that even older ones had blue cables for +12V.
In addition, there were also voltages -12V and -5V (with low current efficiency).

Quarz · Answer

Constant, and the tensions are - for better or worse - stabilized. Look HERE and OVER THERE and OVER THERE , where you need to find an appropriate connector to end the cable coming from the PC power supply. You didn`t write here what form this power supply is; AT or ATX, and their connectors intended for connection to the motherboard differ fundamentally.

Sija · Answer

I don`t know if it is AT or ATX. The power supply was connected to the motherboard with 2 identical (6-pin) cables. Below are the photos:

PS. I also have a question: Is it possible to somehow modify this power supply to provide 12V AC voltage?

Quarz · Answer

This is definitely a Forma AT power supply. Alternating voltage at what frequency?

Sija · Answer

The frequency is irrelevant as long as it produces approximately the same frequency as the simplest 220V/12V mains transformer. I don`t want to buy a transformer, I have no money and I`m afraid I might damage it. Is there any (reasonably easy) way to change from DC to AC??

PS. In fact, there is a thick black wire coming out of it, which ends with a switch. And as zybex wrote, these tips match perfectly. Only there is an orange cable (marked PG in the sketch) What is it for?

zybex · Answer

This is some control related to the motherboard. It`s of no use to you. Just don`t bother with this derivation. If you want to see it in a diagram, look at any AT diagram. There is no point in building a converter that would change the sats into variable ones. It`s easier to buy a small halogen power supply (electronic) for about PLN 20. However, I do not prefer such inventions. Just two days ago, a neighbor had such a power supply. I gave him a toroidal transformer and he will have it forever. The one I mentioned that flew is very small and has a current efficiency of 8.8A at an output of ~11.5V. What current efficiency do you need for these 12V?

Sija · Answer

Sorry for asking such stupid questions, but everyone started somewhere. And what is this current efficiency? And if I were to buy the simplest transformer, what would its price be (approximately) and is it easily available, i.e. I live in a small town and there is one electronics store offering maintenance services and also selling various types of electronic components (I bought diodes there UV and resistors). I mean a specific, easily available model.

PS. I want to power this transformer: Link

Alf73 · Answer

There are 2 basic parameters 1- voltage at which the device operates 2- current needed for proper operation You have a huge database on the Internet with electronic items, lots of stores; If you want some links to stores, write me a PM

zybex · Answer

You can buy a transformer, for example a toroidal one, in any electrical store, because it is used to power halogen bulbs. There are various powers, e.g. 60VA, 80VA or even 200VA and more.

Sija · Answer

When it comes to such a transformer, I have a very similar one removed from the monitor, the same one from which I removed the transformer multiplier.

Sija · Answer

I have a question about this power supply. If I want to connect a 12V bulb to it, should I connect it to +12 and -12 or to 12 and ground?

Quarz · Answer

All voltages provided on the pins of the PC power supply are relative to the common ground potential - black wires.

Sija · Answer

Can anyone tell me what the current efficiency of this power supply is? I mainly care about the current because I wanted to use it to make an electrolyzer and it needs 2A and a voltage of about 3-4V.

Quarz · Answer

Can you read? Look: I guess this is a photo of the power supply in question and posted by you?

Sija · Answer

I actually didn`t notice. And what resistor should I use to obtain 4.5V and 3.6A from a voltage of 12V and a current of 10A? i.e. reduce the initial voltage and current values by 2.7 times? Can I use a regular rotary potentiometer instead of a resistor? CAN ANYONE HELP??!!

Do PC ATX Power Supplies Output AC or DC Current and How to Identify Cable Voltages?

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