PC Power Supply Voltage Data and Connector Types
Contents
Power for Internal Peripheral Devices
Four Pin Molex Power Connector
Molex Drive Connector
Typically used for 5¼ drives such as CD Rom and DVD Drives. Used for legacy IDE, EIDE, and ATA Hard Drives.
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Serial ATA Power Connector
Berg Floppy Power Connector
AMP 171822-4
Typically used for 3½ floppy disk drives.
Six Pin PCI Express Power Connector
PCI Express GFX Connector
MOLEX 39-01-2060
Three Pin Molex KK Type Connector
Typically used for internal cooling fans.
Motherboard Power Connector Types
The eight power supply form factors are:
- PC / XT
- AT/Desk
- AT/Tower
- Baby AT
- LPX
- ATX
- NLX
- SFX
Standard ATX Connectors
Three common ATX power to motherboard connector configurations, a 20 pin connector, a 20 +4 pin connector, and a 24 pin connector. The 20 +4 may be used for either 20 pin connector motherboards or 24 pin connector motherboards. The first 20 pins are a consistent standard on all three configurations.
20 Pin ATX Power
The 20-pin Main power connector is standard for all power supplies conforming to the ATX and ATX12V 1.x form factors, and consists of a Molex Mini-Fit, Jr. connector housing with female terminals. For reference, the connector is Molex part number 39-01-2200 and the terminals are part number 5556.
The total power handling capacity of this connector is only 251 watts, which is lower than many systems need today.
20+4 Pin ATX Power
MOLEX 39-01-2240
24 Pin ATX Power
Technical Notes
- Using a 24 pin power connector on a 20 pin motherboard
The 24 pin male power connector can also be used on a 20 pin motherboard by allowing the four extra to hang off the side, given there is room (one one motherboard example a capacitor is in the way.)
- Using a 20 pin power connector on a 24 pin motherboard
Technically this is also possible to do, however, you risk overloading the 20 pin connector. It is possible to do this because the additional 4 connectors on a 24 pin power connector supply additional voltage to the motherboard into common circuits. Without the additional 4 connectors, you will be drawing more power than the maximum rating through the 20 pin connector which will cause it to overheat.
- A Closer Look at the Extra 4 Power Supply Pins
The 4-pin +12V power connector is specified for all power supplies conforming to the ATX12V form factor, and consists of a Molex Mini-Fit, Jr. connector housing with female terminals. For reference, the connector is Molex part number 39-01-2040 and the terminals are part number 5556. This is the same style of connector as the ATX Main power connector, except with fewer pins.
- Hot-Starting and ATX Power Supply Not Connected to a Motherboard
The old AT style power supplies could easily be turned on when not connected to a motherboard because the switch was mechanical. ATX power supplies are electronically switched via the motherboard. It is possible to turn on an ATX power supply when not connected to a motherboard.
To turn on an ATX power supply not connected to a motherboard short between the green and black wires on the 20 or 24-pin connector, with a paper clip or piece of wire.
Additional Motherboard Power and CPU Power
Six Pin Inline Auxiliary Power Connector
ATX 2.02/2.03 and ATX12V 1.x Auxiliary Power Connector
When more amperage is required by the motherboard before the 24 pin connector was devised, this six pin inline connector was equipped with power supplies to provide supplemental power to the motherboard.
The total power handling capacity of this connector is 58 watts. When combined with the 20 Pin ATX motherboard power connector the total power delivery capability to the motherboard is 309 watts maximum.
Eight Pin CPU Power Connector
MOLEX 39-01-2080
Required connector for modern dual CPU motherboards
AMP ATX 12v Power Connector
AMP 1-480424-0
4 pin connector for the Intel Pentium 4 CPU
