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molex for IDE devices and sata power connector for SATA devices
If you are referring to computers, it is a 6pin power connector for modern Video cards. Most new video cards require at least 1 P12 connector, some require 2 P12 connectors.
Those networking devices ,which not require any type of power (electricity) are called passive networking device,like passive HUB ,its does't require any type of power for working.
This is known as a Coaxial DC power connector. http://en.wikipedia.org/wiki/Coaxial_DC_Power_Connectors
There are two kinds in common use:Molex - an older standard, but still commonSATA - Serial ATA, a newer standardSee the related links for pictures.
No FireWire does not need a separate power supply to operate. FireWire is used to connect peripheral devices to a computer.
The most common power supply connectors for motherboards will be either a 20 or 24 pin connector. Older unit used less pins like the ATX but the cure standard is the 20 or 24 pin main connector.
damage to electronic devices
the regular ATX has a 20 pin power connector, while the enhanced ATX power connector has 24 pin power connector.
The P1 power connector is the first ATX power supplies and motherboards used a single power connector. It also has 20 pins.
Power input connector, or just power connector
Power input connector, or just power connector