In this video from ITFreeTraining, I will have a look at the internal power connectors
that are used inside the computer. These power connectors provide electricity to peripherals
inside your computer and sometimes to the devices outside your computer.
There are many devices in your computer that require power. The typical ones are your hard
disk drive, solid state drive, optical drive and fans. The three main power connectors
for these are the Molex, mini Molex and SATA.
These are the three standard power connectors that are used inside a computer to power devices.
There are other cables that are used to power expansion cards and the motherboard; however,
I will look at these in a different video.
The first connector that I will look at is the Molex connector. Molex connectors were
designed back in the early 1960s. There were many different types of Molex connectors and
they became quite popular in electrical equipment.
In computers, the large Molex connector is the primary one that is used. This male connector
has cylindrical metal sockets. The female connector has cylindrical sprung-metal pins.
The idea being that, when put into the plug, the metal sockets expand to lock the connector
into place.
Although this Molex connector in the old days was quite popular, nowadays this connector
is only used on older devices and some internal fans.
Due to the way the connector is designed, this does mean that some force needs to be
used to plug and unplug these connectors. To prevent the connector being put in the
wrong way, there are chamfers on one side of the connector.
A chamfer is essentially an angular notching on the connector. You can see that these make
the connector angular at the top. When inserting these connectors, make sure that the chamfers
line up. It is possible (using a lot of force) to get the connector in, incorrectly, but
this will most likely damage the device.
If you do get the Molex connector in the wrong way, the power going to the device will be
swapped. As you can see, the red wire is five volts and the yellow wire is 12 volts. When
the connector is reversed, the voltages will be reversed and potentially the device connected
to it will be damaged.
Nowadays this connector is mainly used for older hard disk drives and case fans. On older
motherboards, you may find that there is one of these connectors to provide extra power
to the motherboard. On modern motherboards, due to the increase in the number of wires
used to power the motherboard, you generally don’t find the Molex connector is used anymore,
since the motherboard already has enough power from these wires.
You may also find that some old video cards have a Molex connector, but like the motherboards,
modern power supplies have additional power cables that can be used to supply a video
card’s extra power requirement, rather than using the Molex connector.
The Molex connector is good for big devices, but for small devices it is a little too big.
To make the power connector smaller, the mini Molex or Berg connector was added. This connector
was the same electrically as the larger Molex connector but only smaller. It was primarily
used for floppy disk drives. For this reason, you may see it referred to in documentation
as the floppy disk power connector. Primarily it is used for floppy disk drives; however,
you may find it used in other devices, but not many.
Nowadays, the floppy disk drive is obsolete technology. Very rarely I will use a floppy
disk drive to update an old motherboard’s BIOS, but having said that, most old motherboards
support USB flash RAM. I have not had the need to use the mini Molex connector – I
would say – for the last ten years. For this reason, you will find that some power
supplies will no longer include the mini Molex connector.
The main use of the connector is on the back of the floppy disk drive. It essentially has
four pins. In order to ensure the connector is plugged in the correct way, on the top
of the connector is a notch. This notch is designed to prevent the cable being plugged
in the wrong way. However, if you use enough force you can plug the cable in the wrong
way. It is a lot easier to plug the mini Molex connector in upside down than the Molex connector.
If you ever plug a mini Molex into a floppy disk drive the wrong way up you will know
because the floppy disk drive will emit a certain smell. This is the smell of the electronics
inside the floppy disk drive no longer working.
The Molex connector is quite large. As technology improved, the connector needed to be made
smaller and also support additional features, thus a new connector was required.
To address some of these problems, the SATA power connector was introduced. The SATA connector
is a flat connector which is much smaller than the Molex connector. With devices like
solid-state drives, having a flatter connector became more important because the devices
themselves became flatter.
The SATA power connector has 15 pins. It may seem strange why there are so many pins on
the connector, considering there are only five wires going into the connector from the
power supply. Closer inspection of the power connector will show you that some of the pins
are longer than the others. It is done this way so that when the power plug is plugged
in, some pins are connected before the others. This helps support hot swapping.
Essentially the longer pins transfer power before the shorter pins to give the device
a split-second notice that it is being plugged in. This allows the device to redirect the
initial power away from the device’s electronics. When the device is first plugged in there
can potentially be an overload or arcing over the power connectors. Having the pins staggered
like this allows overload or arching to be transferred away from the electronics which
reduces the chance of damaging the device when it is plugged in.
The SATA power connector adds 3.3 volts of power. Although the SATA power connector is
designed to be compatible with the Molex connector, the 3.3 volt power is not available in the
Molex connector. In the real world, this generally is not a problem because not many devices
use the 3.3 voltage.
The age of your power supply will determine how many of each type of connector you will
have. Newer power supplies will have more SATA connectors than Molex connectors. The
older the power supply gets, the more Molex connectors and fewer SATA connectors it will
have. This is simply because when the power supply was made, the choice of connector matched
what was currently on the market. If you need more connectors than what the power supply
has provided, you can add or convert additional connectors for your needs.
There are a number of splitters and converters that are available on the market. For example,
there is a Molex to SATA converter. Keep in mind that Molex does not have a 3.3-volt wire,
but since most devices on the market do not use the 3.3 volts, generally this is not a
problem.
If you need more connectors, you can use a splitter. For example, split a Molex connector
into two SATA connectors. You could also split a Molex into two Molex connectors. Using a
few of these to increase your connectors should not cause any problems. However, keep in mind
that these put more load on your power supply. If you start using a few of them, you may
need to consider getting a larger power supply!
This concludes this video on internal power cables inside your computer. I hope you have
found this video useful and I look forward to seeing you in the next video from us. Until
that video, I would like to thank you for watching.