Types of power supply connectors and different functions

Types of power supply connectors and different functions

The power supply or PSU (Power Supply Unit) is a very important element in desktop computers, since it is responsible for supplying and managing the energy in our PC (that is why we dedicate a specific article to them to know which model to choose ).

To do this, it obtains it from the cable connected to the network and through a transformer and a circuit board, it will give different voltage outputs to be able to feed each internal component of the box or tower.

Each of those voltage outlets have different connections or molexes to connect to the motherboard, installed optical drives, hard drives, etc.

These connectors are vital when choosing a power supply, and not only the power supported or the active or passive protection technologies they have.

wire colors

Not all power supplies use colored cables , but it is popular that we find cables with different colors to distinguish them.

Others, for aesthetic reasons, only use a single color, which makes it more difficult to know the characteristics of each one.

The colors can help us use a multimeter or multitester to check the voltages and thus determine if a connector is failing or not.

  • Black : It is the ground wire, that is, GND or 0v .
  • Red : corresponds to the +5v voltage.
  • Yellow : it is the other standard voltage cable like the previous two, but in this case it is +12v.
  • Yellow with black line – Voltage is like yellow, but is present on newer power supplies for processor power on a separate 4-pin connector.
  • Orange – This is also a standard voltage power cable, in this case +3.3v.
  • White – It has already disappeared from new power supplies, so it will be rare for us to find it. It corresponded to -5v, and was limited to 1A intensity.
  • Blue : like yellow it provides -12v at a very low current intensity (limited to 1A).
  • Brown : it does not correspond to a power cable like the first ones, but it does serve to regulate the 3.3v line.
  • Pink : same as above but for the +5v.
  • Green : used to turn on the source.
  • Grey : another test cable, in this case it is the famous Power Good, a necessary signal to check that everything is OK in the PSU.
  • Purple : Lastly, we have the +5v for the Standby state.

Knowing this, by inserting the tips of our multimeter into the contacts of the connectors, we will be able to know if the voltages are what they should be based on the color. If this is not the case, we will have a power supply that we will have to repair or replace.

Types of power supply connectors and different functions

Connections of a PSU

We are going to see some of the connections of the most popular power supplies in current systems, their characteristics and what each one is for:


The Berg connector is an old connector used for the floppy drive. It is small in size and has 4 cables, two for ground and another for +5 and +12v.


The molex is the most typical of the connectors, since it is used to connect IDE ATA drives such as CD, DVD, BD drives, hard drives, etc. Like the Berg, it also has 4 wires and 4 contacts, but its size is larger.

By the way, you should know that there are male and female types . You can see both connectors in the image above. On the left we have an example of a male and on the right the female.


It is a more modern connector that is displacing the previous one. This type of connector is thinner than molex, and has more contacts to supply power to SATA or newer hard drives and drives.


The PCI Express connector can be found in two modes, one with 6 pins (4+2) and the other with 8 pins. As you can imagine, it is used to supply extra power to the most powerful PCIe graphics cards.

These types of high-end graphics cards demand large amounts of power, so the 6-pin connector can supply an extra 75w by connecting it directly to the connection provided by this type of card.

If it didn’t connect, in many cases it would work but at lower performance.After this modality, the 8-pin modality was devised , which has the same connection, but in this case it can reach powers of up to 125 extra watts.


Not to be confused with the 8-pin PCIe, despite their resemblance they are different. It is a connector that we will not easily find on PCs,

since it is intended more for servers or workstations with motherboards that have more than one socket, that is, MP systems. The EPS will supply an additional 12v of power for those boards with more chips, 4 and 4 can be connected separately, or together to form an 8 pin connector.

20-pin ATX:

It is a fairly old connector and currently in disuse, introduced in the 90s. It is used to supply power to ATX motherboards thanks to its 20 pins. It includes the different standard voltages for all components on the motherboard.

ATX2 o ATX 24 pines (20+4):

Current motherboards need an extra current supply, which is why this evolution of the previous one has been implemented, adding an additional 4-pin connector.

Typically, all 20 can be joined together to form a single connector, or separated to connect independently, thus adding compatibility for older boards.

Adapters and duplicators

There are also adapters to convert these connectors into different ones if necessary. For example, sometimes we may not have too many 4-pin molex drives , and we do install multiple SATA drives.

If we no longer have any more SATA connections but we do have free molex connections that are not being used, you can use this type of adapter to transform them into the connection you need.

James Hope
My name's James and throughout the long term. I have actually assembled numerous PCs for me as well as my companions. I love gaming, programming, illustrations planning and essentially whatever has to do with PCs and innovation.