Some call this "junk closet". But frankly, i call it "Museum".
All devices needs of power to operate. The power to computer devices, is delivered through cables that are connected using the "Molex" connectors. Searching inside my museum, i found almost all these connectors to demonstrate.
A few historical facts
What is a Molex connector? Or better, what is a "Molex"? The Molex is a kind of plastic that was invented by a company named "Molex" in the 1930s. The material was developed by Frederick August Krehbiel, and in 1938 he founded the Molex Products Company. The company produced flower pots, toys, salt tablet dispensers, clock cases, and insulators out of this material. In 1953, Molex introduced the first connector, called "686 Plug".
Today, computers have numerous molex connectors inside. This article will line up these connectors and the pinout configuration shall be given, for those who just want to know, or those who thinks of moding the case a little bit.
Motherboard power supply
PC 6+6 pins power supply
The 6+6 power supply (1981). "Black with black" or a toasted motherboard
In 1981, the new PC was introduced. It required 2 cables, 6 pins each for the power supply. Although the connectors were polarized, the keys could be easily misplaced with a little force. Thus, various expressions were "invented" to avoid a smoking (and quite expensive) motherboard, such as "black with black", that meant that the plugs should be connected in a way that the black wires at their sides, should be side by side.
The 20pins ATX power supply connector (1992) had better keys to polarize and 3 brand new features!
During the year 1995, the new ATX standard was introduced with 20 pins connectors and 3 brand new lines: the 3.3 volts power supply cable, the sleep power supply that has +5 volts even when the PC was off, and the Power On cable that can turn on the power supply from a motherboard command and not only from the hardware switch. The keys of this connector were re-designed and thus it could not be entered the wrong way.
*VSB = Voltage StandBy. +5V could be delivered to the motherboard even when the computer was turned off
ATX 24 pins power supply
The new ATX 24 pin connector, has all the features of the old 20-pin, plus a ground,a +5, a +12 and a +3.3 volts supply line.
During the 20-24 change era, it was very common the power supplies to have a 20 pins connector and a 4 pins connector together....
...and these connectors could be jointed into one 24-pins connector!
Until now, the motherboard was powered with an 20 pins connector. If more power was required, most power supplies had an extra 4-pins connector for this. So, these two connectors jointed together to perform the new 24-pins connector. It has all the features that the old 20-pins had, plus a ground, a +5V, a +12V and a +3.3V power supply line. It is physically polarized to avoid errors in connection.
@Roger Cole for small signals you may wanna use RJ connectors, like the ones used on telephones and ethernet cables. They come in different sizes with 2,4,5,8 wires and they are pretty small. This is what i would use for small signals. For high current rates, polarized headers such as these are ggood:
Great resource as has been said. I am looking for a plug/socket to adapt a six-wire 12v house thermostat controller. Based on reading this, (a) I can forget about using the ATX 6 pin as being too rare but (b) looks like I could use two peripheral 4-pin plugs or (c) the PCI Express 6=pin. The latter looks like overkill for the small signals and currents there will be and I am thinking option (b). Any thoughts appreciated!
@Mark Green each connector has a different key, so that they cannot be connected wrong. You may wanna check the keys to ensure that they do connect there. If you see closely the conneters you will notice that each pin may be rectangular, or like a roof top. The same "keys" applies to the the connector receptacles on the motherboard. This way, you cannot put wrong connectors.