PC Power Connectors – CompTIA A+ 220-801: 1.8

| October 15, 2012

If you look closely at your computer’s power supply, you’ll see a myriad of different cables used to power the internals of your PC. In this video, you’ll learn about all of these connectors and how they can be used to power the motherboard and peripherals inside of your computer.

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Review Quiz: PC Power Connectors

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If you unplug your computer and open up the desktop case and look inside, one of the largest boxes in there will be a power supply. It looks something like this. And there will be a lot of cables coming out of the back of that power supply with a lot of different types of connectors on it. Each one of these connectors correlates to another part of your system, and in some cases, these connectors work with each other to make sure your motherboard, your video cards, and the other devices inside of your computer are powered on properly.

The motherboard of your computer has probably one of the largest power connectors that you’ll find on your computer system. It’s either a 20- or 24-pin power connector. We used to just use 20, and as the standards increased and we needed more power for our motherboards, we increased this to be a 24-pin connector. And even today, you can find some motherboard power supplies that are set up with a 20-pin and an extra 4-pin off to the side in case you need to use that power supply in an older system.

There are many different voltages going through this particular power connector, and it’s very, very easy to find it on your motherboard. If you look at all the connections on your motherboard for your CPU, and your memory, and your adapter cards, you’ll see a really large 20- or 24-pin connector right on the motherboard. It is one of the biggest connectors on that device, very, very easy to find. And that is where you would simply plug in that connection directly from your power supply right into the motherboard.

One of the most common power connection types is this 4-pin power connection that we call a Molex connection. The name Molex actually refers to the manufacturer of this particular connection. Molex is a very large organization that makes many, many different types of connections, but because this is the type that we found inside of our computers, it now has this moniker of the Molex connector.

And what we’re really talking about is this 4-pin power connector. You can see that it is slanted on one side of it, so that it can only fit into a power connection that is exactly that size. And generally, you’re using this to power types of peripherals inside of your computer case– storage devices, CD ROMs, and DVD ROMs. Maybe fans might be connected to these. We would be using these because they’re such a very common connection type for power inside of the computer case.

As the capabilities of our motherboards increased, we found we needed more power. We had already increased the power connector up to a 24-pin connector. And so we started changing the standards to add different types of connectors onto that. One of these is a 4-pin. This is for the ATX12 volt standard. Sometimes you’ll see this referred to as a P4 connector. And it’s really designed to give additional power along with that 24-pin connection.

There is also an 8-pin connection. This is from a standard called the EPS12 volt, an entry-level power supply specification. It was really designed for servers and devices that had multiple processors and multiple cores in those processors that needed a lot of power. Those will have eight pins connected to it. And you’ll see them used in conjunction with that 24-pin power connection on the motherboard.

The motherboard isn’t the only thing that needs a lot of power on our modern computer systems. Our PCI Express slots occasionally have connections on them that need more power as well. And so we created this standard that provided both 6 pin and 8 pin PCI Express power, exclusively for those adapter cards that were plugging into the PCI Express bus.

And you can see, the 6-pin is a 75 watt. The 8-pin is a 150 watt. And if you’re wondering what would need that much power on a PCI Express, you’ve probably already guessed it’s something like a video card. Today’s video cards are extremely powerful. They have multiple processors on them. There’s usually a fan connected to them.

A lot of power needs to go to these devices. And if you look carefully at the very top of this particular video card, you’ll see those connectors are right in the top. So if you need additional power to your PCI Express adapters, there’s probably going to be a connector right on the device card itself. Simply look for that connection, and plug-in to that power.

Our storage devices also need power. And if you have a SATA drive, it may not necessarily be using that 4-pin Molex connector that we looked at earlier. This particular SATA drive that I have is one the earlier SATA drives that was in a transition period.

You could use the standard SATA power connection, which is this connection on the far left of this view. Or it also allowed you to use a Molex connector if that’s all you had in the power supply that you were using. Today the newest SATA drives generally only have that single SATA power connection. And you can see, it is a very specific kind of connector. There’s nothing else on your computer that’s going to be using this.

And if you do have an older power supply that does have that Molex connector, you might want to get something like this device that will take a Molex connection coming in and convert it into this SATA power so that you can then power your hard drive.

If you have a floppy drive inside of your computer, you’ll notice that it has a very unique connector on it for power. This is a 4-pin connector. It’s relatively small. And we have generically just called this the floppy drive connector. Sometimes you’ll also hear it referred to as a berg connector. If we were to compare, for instance— here is a CD-ROM drive and the big Molex connector that’s on it.

Notice that the power for the floppy drive, much smaller, very diminutive in comparison. Let’s zoom up on that and have a look. It’s just a small 4-pen connection. It does have a key on it with this connection on it, so you can only plug the power in a certain way. That makes it very, very simple to find that power connection for the floppy drive and plug it right in so that you have power going to the floppy drive connection.

Now that you can recognize some of these common power connections, try unplugging your desktop computer, taking the cover off, and seeing if you can identify all of the power connections going to your motherboard and all of the peripherals inside of your computer.

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Category: CompTIA A+ 220-801

Comments (1)

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  1. Awesome Videos Professor. My A+ 801 is in 12 days from today. I hope to excel as I supplement my self study with your videos.

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