Moles plug
The name Molex connector is due to the Molex company. The Molex connector is a robust plug that is used to provide the power supply from the power supply unit to the drives and the fan. It is available as a 2-, 3- and 4- pin connector for supplying power to fans, floppy, CD and hard disk drives.
The plug contacts of the Molex connector are next to each other and their connections are color-coded. The plug contacts are sockets that are recessed into the plug body. The plug contacts themselves are located on the connected component. To prevent the connector from twisting, they have flattened guides on two edges. Molex connectors come in two sizes, with the smaller version intended for small floppy drives.
On the four-pin Molex connector used to power hard disk and CD drives, the two middle connectors are black and connected to ground. The yellow connector carries a voltage of 12 V, the red one 5 V.