POWER SUPPLY UNIT-SMPS (SWITCH MODE POWER SUPPLY)
A power supply unit (PSU) is the component that supplies power to the other components in a computer. More specifically, a power supply unit is typically designed to convert general-purpose alternating current (AC) electric power from the mains (100-127V in North America, parts of South America, Japan, and Taiwan; 220-240V in most of the rest of the world) to usable low-voltage DC power for the internal components of the computer. Some power supplies have a switch to change between 230 V and 115 V. Other models have automatic sensors that switch input voltage automatically, or are able to accept any voltage between those limits.
The most common computer power supplies are built to conform to the ATX form factor. This enables different power supplies to be interchangeable with different components inside the computer. ATX power supplies also are designed to turn on and off using a signal from the motherboard, and provide support for modern functions such as the standby mode available in many computers. The most recent specification of the ATX standard PSU as of mid-2008 is version 2.31.
Note that some manufacturers, most notably Compaq and Dell, have produced power supplies using the same connectors as ATX but with different voltages on different pins; mismatching such PSUs and motherboards can result in damage to either or both
PC Main power connector (usually called P1): Is the connector that goes to the motherboard to provide it with power. The connector has 20 or 24 pins. One of the pins belongs to the PS-ON wire (it is usually green). This connector is the largest of all the connectors. In older AT power supplies, this connector was split in two: P8 and P9. A power supply with a 24-pin connector can be used on a motherboard with a 20-pin connector. In cases where the motherboard has a 24-pin connector, some power supplies come with two connectors (one with 20-pin and other with 4-pin) which can be used together to form the 24-pin connector.
ATX12V 4-pin power connector (also called the P4 power connector). A second connector that goes to the motherboard (in addition to the main 24-pin connector) to supply dedicated power for the processor. For high-end motherboards and processors, more power is required, therefore EPS12V has an 8 pin connector.
4-pin Peripheral power connectors (usually called Molex for its manufacturer): These are the other, smaller connectors that go to the various disk drives of the computer. Most of them have four wires: two black, one red, and one yellow. Unlike the standard mains electrical wire color-coding, each black wire is a ground, the red wire is +5 V, and the yellow wire is +12 V. In some cases these are also used to provide additional power to PCI cards such as FireWire 800 cards.
4-pin Berg power connectors (usually called Mini-connector or "mini-Molex"): This is one of the smallest connectors that supplies the floppy drive with power. In some cases, it can be used as an auxiliary connector for AGP video cards. Its cable configuration is similar to the Peripheral connector.
Auxiliary power connectors: There are several types of auxiliary connectors designed to provide additional power if it is needed.
Serial ATA power connectors: a 15-pin connector for components which use SATA power plugs. This connector supplies power at three different voltages: +3.3, +5, and +12 volts.
6-pin Most modern computer power supplies include 6-pin connectors which are generally used for PCI Express graphics cards, but a newly introduced 8-pin connector should be seen on the latest model power supplies. Each PCI Express 6-pin connector can output a maximum of 75 W.
6+2 pin For the purpose of backwards compatibility, some connectors designed for use with PCI Express graphics cards feature this kind of pin configuration. It allows either a 6-pin card or an 8-pin card to be connected by using two separate connection modules wired into the same sheath: one with 6 pins and another with 2 pins.
A C14 IEC connector with an appropriate C13 cord is used to attach the power supply to the local power grid.
AT vs. ATX
Wiring diagramsAT power connector (Used on older AT style mainboards)
The particular pins are pin number 14 and 15. Well, to identify the pins, simply do the following. Hold the ATX power connector with the notch facing towards you. There are two rows of 10 pins each; one closer to the notch (row B) and one on the other side (row A). The first pin from the right on Row A is pin 1 and the one on the extreme left is pin 10. Pins 2 to 9 understandably lie in between. Now move to Row B. The rightmost pin is pin 11. Start counting from right to left till you locate pins 14 and 15. You need to short these two pins. Still confused? Check out the following image... that should help you out. Mind you, we are talking about an SMPS with a 20-pin connector.
When finished with locating the pins, take a small piece of copper insulated wire and open the ends up. Twist the strands at each end to make them stiff enough to hold on to the innards of the plug. Next, insert one end into the socket of pin 14 and the other in socket 15. After inserting the ends inside the sockets, use some scotch tape or insulation tape to secure the wire from falling off. Place the SMPS in a location away from your processor socket to prevent the hot air from blasting onto the processor heat sink and raising the temperature further.
You can keep the SMPS outside the cabinet provided the power cables are long enough to reach the other devices. Next, plug in the power connectors to the devices and close your cabinet. Yes, there has to be a small gap or a groove somewhere for the necessary cables to enter the cabinet. Attach a power cord to the extra SMPS and turn the switch on. Now, turn the main PC on. Make sure your second SMPS is also on, in case you have hard disk drives attached to it. This must be done in such a manner as during boot time, the power on signal invokes the MBR loader in each hard disk, thereby, other drives connected to the second SMPS will either not be recognized by the BIOS or will take a long time to boot. Also, be sure not to turn off the second SMPS while running Windows, in case there are any hard drives attached to it. That way, you may stand to lose data. A smart thing to do would be to connect all your hard drives to the main SMPS and your cooling equipment to the secondary SMPS. This includes all the fans as well as any super turbine cooler engines you may have installed.
There you go. You are a lot more powerful now. I mean you have more power at your disposal. Now, this may not be the most aesthetically appealing setup but can prove extremely effective in terms of both, power and cost. Certainly worth a try if you need that extra power and don't have deep pockets.