Everything You Need to Know About Power Supplies

Pin-Out

• ATX12V v2.x Motherboard Power Connector

Pin	Color	Output
1	Orange	+3.3V
2	Orange	+3.3V
3	Black	Ground
4	Red	+5V
5	Black	Ground
6	Red	+5V
7	Black	Ground
8	Gray	Power Good
9	Purple	+5VSB
10	Yellow	+12V
11	Yellow	+12V
12	Orange	+3.3V
13	Orange	+3.3V
14	Blue	-12V
15	Black	Ground
16	Green	Power On
17	Black	Ground
18	Black	Ground
19	Black	Ground
20	White	-5V
21	Red	+5V
22	Red	+5V
23	Red	+5V
24	Black	Ground

• EPS12V Connector

Pin	Color	Output
1	Black	Ground
2	Black	Ground
3	Black	Ground
4	Black	Ground
5	Yellow	+12V
6	Yellow	+12V
7	Yellow	+12V
8	Yellow	+12V

• ATX12V Connector

Pin	Color	Output
1	Black	Ground
2	Black	Ground
3	Yellow	+12V
4	Yellow	+12V

• PCI Express 6-Pin Auxiliary Connector (PEG)

Pin	Color	Output
1	Yellow	+12V
2	*	*
3	Yellow	+12V
4	Black	Ground
5	Black	Ground
6	†	Sense0†

* The PCI Express specification says this pin must be left unconnected. However, the EPS12V specification says this pin must be used for +12 V (yellow wire).

† The Sense0 pin generates a code for the video card to know which kind of power connector is available. When this pin is grounded (black wire) and the Sense1 pin is not available (which is the case), this indicates that the auxiliary power connector is a six-pin one. Therefore, six-pin connectors have this pin grounded.

• PCI Express 8-Pin Auxiliary Connector (PEG)

Pin	Color	Output
1	Yellow	+12V
2	Yellow	+12V
3	Yellow	+12V
4	†	Sense1†
5	Black	Ground
6	Black	Ground
7	Black	Ground
8	†	Sense0†

† The Sense0 and Sense1 pins form a code that tells the video card which kind of power connector is available. When both are grounded (black wire), this tells the video card that an eight-pin connector is used. This is the reason why on eight-pin connector pins four and six are grounded.

• Serial ATA Power Connector

Pin	Color	Output
1	Orange	+3.3V
2	Orange	+3.3V
3	Orange	+3.3V
4	Black	Ground
5	Black	Ground
6	Black	Ground
7	Red	+5V
8	Red	+5V
9	Red	+5V
10	Black	Ground
11	Black	Ground
12	Black	Ground
13	Yellow	+12V
14	Yellow	+12V
15	Yellow	+12V

• Peripheral Power Connector

Pin	Color	Output
1	Yellow	+12V
2	Black	Ground
3	Black	Ground
4	Red	+5V

• Floppy Disk Drive Power Connector

Pin	Color	Output
1	Red	+5V
2	Black	Ground
3	Black	Ground
4	Yellow	+12V

• ATX12V v1.x/ATX Motherboard Power Connector

Pin	Color	Output
1	Orange	+3.3V
2	Orange	+3.3V
3	Black	Ground
4	Red	+5V
5	Black	Ground
6	Red	+5V
7	Black	Ground
8	Gray	Power Good
9	Purple	+5VSB
10	Yellow	+12V
11	Orange	+3.3V
12	Blue	-12V
13	Black	Ground
14	Green	Power On
15	Black	Ground
16	Black	Ground
17	Black	Ground
18	White	-5V
19	Red	+5V
20	Red	+5V

• ATX12V v1.x Auxiliary Connector

Pin	Color	Output
1	Black	Ground
2	Black	Ground
3	Black	Ground
4	Orange	+3.3V
5	Orange	+3.3V
6	Red	+5V

• AT Power Connector

Pin	Color	Output
1	Orange	Power Good
2	Red	+5V
3	Yellow	+12V
4	Blue	-12V
5	Black	Ground
6	Black	Ground
7	Black	Ground
8	Black	Ground
9	White	-5V
10	Red	+5V
11	Red	+5V
12	Red	+5V

Frequently Asked Questions

What are the types of power supplies, in short?

• SMPS- Switched Mode Power Supply
• Uninterruptible Power Supply
• AC Power Supply
• DC Power Supply
• Regulated Power Supply
• Programmable Power Supply
• Computer Power Supply
• Linear Power Supply

Can a battery be considered a power supply?

Sure, in layman’s terms, a battery can also be considered a power supply. However, you shouldn’t use that term unironically when referring to a battery, as it can create tons of confusion. A power supply, unlike a battery, is constant power and can usually be set over a wide scale of voltage and/or current. This unit gets its power usually from the grid or mains.

Which is better: AC or DC?

Alternating current is cheaper to generate and has fewer energy losses than direct current when transmitting electricity over long distances. Although for very long distances (more than 1000 km), direct current can often be better. It depends on multiple factors, as you can already tell if you’ve taken your sweet time to read through our entire comprehensive article.

Why is Direct Current not used for transmission over Alternating Current in so many countries?

As mentioned in the previous question’s answer, alternating current is simply cheaper. Moreover, for most intents and purposes, the direct current would have to be converted to alternating current anyway, which, again, pumps up the consumption and the cost as a result.

Why is power loss less noticeable when dealing with alternative current instead of direct current?

Direct current becomes efficient when you need to transfer power over more than 1000 kilometers. Very few infrastructures actually have that much distance between the power plant and regular households without any secondary stations or power plants in between.

Final Thoughts

We hope you’ve enjoyed our article and that you’ve found at least a few bits of useful information throughout it. Feel free. toleave any questions in the comments.