A PC's power supply takes AC power from the grid and transforms it into DC voltage the system needs to run.
- What we're looking at here is an ATX style power supply, the predominant power supply used in desktop PCs today. In this episode, I just want to do a quick run through of the power supply, introduce it to you, show basically its function and some of the connectors on it, and then we'll go ahead and put it into a system. So let's start off by just taking a look at this box. So what I've got here, on one end, this is the part that's outside that you would see from the outside world. This is where I plug into a standard wall outlet, hopefully via a surge suppressor or something. Now, there are a couple other things. Number one, you're going to see there's pretty much always an on to off switch. This isn't what we use to actually turn on the computer. This is just giving the power supply juice itself. There'll be a button in the front for us to actually turn it on. It's also a great way, if you turn that off, people never think to check that, and they're like why doesn't the computer turn? The other thing you're going to notice is... I'm going to tilt up so we can see this. This little red connector on this particular one, it's a slider. It's not a connector. That's for European voltages 230 volts or North American voltages being at around 120 volts. So if I was in England, for example, I would flip that to 230, and then I could plug into English power, or if I flipped it back to 110, I could plug into the United States. These are pretty rare today, as most power supplies are auto-sensing and will automatically adjust to any input voltage, which is pretty cool. All right, so you also can probably see other fans. In general, power supplies like to be the one that the air goes through. So air comes into your case from other places and goes out through the power supply, although we can see, in more modern power supplies, there might be exceptions to that. So first of all, power supplies don't really supply power. The power comes from your power company. What these really are are step-down transformers that convert AC power into DC power. So let's take a look at some of the connectors and all of these many, many guys that actually plug into your system itself. So I want to start with this guy right here. So this is the primary ATX power connector for the motherboard. Now, if you take a look at this, you'll see it's kind of in two pieces. The original ATX standard had a 20-pin connector that plugged onto every motherboard there was, although later they found out they needed more power, and they added four more pins. So you'll see on a lot of power supplies where that's kind of two, two, two pieces in one. Now, as we're looking at this, I want you to notice some colors here. There are three main types of power that power supplies provide, 12 volt, five volt, and 3.3 volt. If you see a yellow connector, that means it's providing 12 volt. If you see red, those are providing five volt, and if you see orange, they're providing 3.3. As for the other colors, well, just keep watching. We'll talk about some of those other colors as we continue through. Now, on the original ATX standard, we only needed this one power connector, and that provided all the motherboard power. However, over time, CPUs got bigger and more powerful and needed more electricity, and we began to discover that we needed more power. So they came up with what was known as, still is known as ATX 12V. The ATX 12V standards basically are extensions to the original ATX power that allow us to put more electricity into the motherboard. On this particular system, always so much fun digging through these, this is an ATX 12V extension power. These also plug into the motherboard. On some motherboards, it only needs one of these. On other motherboards, it's going to use both of these. It really depends on the motherboard. There's a lot of flexibility here, and also on some, motherboards only have six connectors, and only six of these eight plug in, and you can use this, and it plugs in, and two of them just hang there, and everything's fine. So that's what actually powers the motherboard, but inside the case, you've got a lot more than that. You got hard drives, and you've got video cards, and you've got all kinds of other stuff, and they need electricity, too. So that's why we have all these other connectors on here. So I'm going to do a quick little march through, making sure that you're aware of these different types of connectors. Okay, here we go. This first connector we see right here, this is the oldest power connector that is on any system, and it's known generically as a Molex. Molex connectors are very general purpose, and you can tell by the colors they provide both five volt and 12 volt. They were used for many decades to power the insides of systems. They're falling out a little bit, although there's plenty of stuff that uses Molexes. This right here is what we call a mini connector. It was originally designed to run a component known as a floppy drive. It's the component of your forefathers. Floppy drives are dead, but we still see components from time to time that need these little mini connectors to provide power. Now the one thing on these connectors you need to be aware of is that they have chamfers. They have little notches or something on 'em that prevent you from plugging them in backwards. So with power connectors, it's really, really hard to make a mistake. If it isn't going in pretty straightforward, you're doin' it wrong. Now, as we move into more modern systems, we see connectors like this. This is a SATA power connection. It's used primarily for hard drives, although you'll see it on, for example, optical media, things like that that might also use this for power, and the last one I want to show ya is what we call a PCIE connector. These connectors are used for video cards. Higher-end video cards need their own little extra bit of juice, and these are dedicated connectors that you plug straight into your video card to give your video cards just that little bit of extra power that they need. Now, if you take a look at this power supply, you'll see that all these cables are just soldered onto the system. So what if I have a smaller system that doesn't need all this? Well, you used to wind these up with twist ties and try to hide them as best you could. However, what's very popular today is something like this. So this is what we call a modular connector. Note that it's got a whole bunch of connectors here. There's no cables coming off of it. That's because also in the box it came with are all of these extra cables that you can choose to use or not use based on what your system needs. Now, I'm definitely going to need some motherboard power. So it's got its own little dedicated connection here. I'm going to just plug this in, (rattling) and again, they're chamfered, so I can't put 'em in backwards, but they can be a little persnickety, especially with a brand-new power supply like this, and I know I'm going to need some supplemental power for my motherboard, and this one has one of these. So what I've just done here, I just want to make sure you see the connectors here. You'll see I've plugged in my ATX power motherboard connectors so they're on and ready to go. In terms of plugging anything else in, one of the nice parts about modular power supplies like this is that I probably won't plug anything else into the back of this power supply until I know what that particular motherboard needs, and in order to do that, let's go ahead and mount this power supply into a case.
- Troubleshooting firmware
- Installing a motherboard
- Basic electrical terminology
- Mounting and choosing a power supply
- Cooling your PC
- Quickly troubleshooting power supplies