Motherboard Connectors – CompTIA A+ 220-1101 – 3.4

Our motherboards provide connection and communication between many different components. In this video, you’ll learn about main power connectors, 4-pin ATX power connectors, SATA connectors, and pin headers.

One of the largest connectors on your motherboard is one that is providing power directly from the power supply to the motherboard. This provides main motherboard power at 3.3 volts plus or minus 5 volts and plus or minus 12 volts. Originally, this was a 20-pin connector. And as the years have gone by, we’ve needed some additional power for the motherboard.

So now, the standard size for this motherboard power connector is a 24-pin connector. If you have a motherboard with an older 20-pin connector, you can still plug in this 24-pin connector and use it. Some power supplies even have this connector modular, so it has 20 pins and then you can attach 4 more pins to it.

Here’s a view of this 24-pin connector on a motherboard, and you can see that the individual pins on the connector are keyed. This ensures that the connector can only be inserted one particular way into the motherboard and cannot be accidentally turned around or plugged in with the wrong orientation. The connector itself also has these same keys, and you can see that some of these pins have notches while others are completely squared off.

Before connecting the power supply to the motherboard, you want to first make sure that you’ve disconnected from all power sources and then connect that directly into the motherboard with the orientation that matches the keys on the individual pins. On this particular connector, there is a lock on the side of it that corresponds with this lip that is coming off the end of the connector so that, when you push it down into the connector, it locks in place. And this will not move out of that connection until you push down and unlock it from the power connector.

Some motherboards need additional power for the CPU. And usually, these connectors are physically located somewhere near the CPU itself. This is a 4-pin ATX connector. That “ATX” stands for “Advanced Technology Extended,” and it refers to a family of motherboards. This is a connector that provides 12 volts power, usually for the CPU that’s on the motherboard. These connectors are usually labeled as “CPU,” “P4,” or it might have written on it “ATX 12 volt.” And there are keys on these connectors as well, so there’s only one way to plug this in to the motherboard.

Here’s a motherboard that does not have a CPU installed yet, but you can see the CPU socket is at the bottom. And here near the top of the image is the 4-pin connector. It even says on the motherboard ATX 12 volt, referring to the 12 volt power that’s provided on that connection. You’ll also find a number of storage connections on the motherboard. One of these would be SATA connections. These colored connectors are the SATA, or Serial ATA, connectors that are commonly used to connect hard drives and SSDs.

Some motherboards will have different types of connections. They may be in a different layout, or they may be a different color. But all of this is exactly the same SATA connection, and you would use these connections for any of your storage devices. There may be situations where you don’t have any room to install a new drive inside of your computer case or perhaps you have an external drive that you would like to use.

In those cases, you might want to use an eSATA connection for external Serial ATA. That external connection is usually provided with a built-in interface on the motherboard. Or in this particular example, it’s an expansion card that adds additional eSATA connectors to the back of this computer. This allows us to connect an external storage device, but we still have the same throughput and performance as an internal SATA connection.

Another important set of connectors on your motherboard are the headers. Sometimes, you’ll hear these referred to as “pin headers,” because they are groups of pins that are on the edge of the motherboard. There’s usually a single large connector or a number of smaller individual wires that would connect to all of these pin headers. These might provide power or have USB connectivity, or they might provide the button connectivity that you have on the outside of your computer case.

On this motherboard, these pin connections are at the bottom. And you can see, there are a number of different groupings of pins. Some of them are labeled “AAFP.” This is referring to the external audio connectors that are on the case of your computer. And there are other connectors on here, some for USB and others for other audio functions. If you look closely at the motherboard, you can often tell exactly what the pin headers are used for.

On this motherboard, there are five different groups of pin headers. You’ve got a TPM. That is for the Trusted Platform Module to plug in. You’ve got two USB connectors, probably for a Legacy USB connection. And then you’ve got two USB 3.0 connectors that are also on the motherboard as pin headers. And some of the pin headers on your motherboard provide power and control for the cooling fans.

Many computer cases have an on/off button on the case. There might be a reset button, and there might be other controls as well. The way that you integrate those buttons with the motherboard itself is through connectors that are provided on the case. These connectors are even labeled. These are the connectors used for the reset switch. Here’s another one for the hard drive light and another connector here for the power light. You would then connect those case connectors to the pins that are on the motherboard, and this motherboard even labels where you would connect those pins. These two are for the power connection. Here’s the connection for the reset button and so on.

Here’s a view that includes both the case, the wires coming from the case, and the connectors that are plugging into the motherboard. You can see where the external connectors and lights are connected to the case itself, and then the wires are plugged into those pins that are on the motherboard. Here’s a closer connection. It looks like these connectors are plugging into USB interfaces that happen to be on the front of that computer case.

You might also find on your motherboard an M.2 connector. This is on newer motherboards that can support connectivity using this M.2 standard. One very common use of these M.2 connectors is to plug in an SSD and be able to have all of your storage on this very small device connected to the motherboard. To use this, you would simply plug into the M.2 connector on the motherboard. You would push the drive all the way into the M.2 connector and then fasten it to the motherboard with a screw. This will ensure that whatever you’re connecting into that M,2 interface will be firmly fastened to the motherboard itself.