Power Connector and Voltage Regulator

Power Connectors:-

     
                The motherboard has a socket to attach the power cables coming from the power supply. ATX form factor motherboards  and power supplies use a single 20-wire motherboard power cable. All others use a pair or 6-wire cables.

                     The cables are connected to the motherboard so that the black wires are together in the middle. This connector is usually found near the back right-hand side of the motherboard, near the power supply.

Voltage Regulators:-

       In old days, devices used to run on same voltage of 5V. The arrival if processors and other devices  running at different voltages led to the necessity of motherboards. These regulators reduce the 5V signal to those voltages typically needed by processors: 3.3V or lower.

        Processor manufacturers fit in a dual voltage scheme into their latest designs. The processor is fed two voltages: the external or "I/O" voltage is typically 3.3V, while the internal or "core" voltage is lower: usually 2.8 to 3.2 volts. The voltage regulator is responsible for generating the correct voltage for the processor.

       The voltage regulator can normally be identified by the large heat-sinks that are placed on it; Voltage conversion generates a great deal of heat. On many motherboards, the cooling level of the entire system case is important to ensure that the voltage regulators are cooled satisfactorily. Overheating regulators can cause lockups and other problems.

Motherboard Components(Bus)

Why Bus:-
           A personal computer may transfer data from disk to CPU, from CPU to memory, or from memory to the display adapter. A PC cannot afford to have separate circuits between every pair of devices. A mechanical switch, like the old phone systems used, would be too slow. So we can use bus.

Bus:-
         

              The Bus is simply a common set of wires that connect all the computer devices and chips together. (or) A bus is a common pathway across which data can travel within the computer. This pathway is used for communication and can be established between two or more computer elements. A PC has many kinds of buses, including the following:

•  Processor bus
•  Address bus
•  I/O bus
•  Memory bus

Processor Bus:-
         The processor bus is a communication pathway between the CPU and immediate support chips. These support chips are usually called the chipset in modern systems. This bus is used to transfer data between the CPU and the main system bus.

Address Bus:-
        The address bus actually is a subset of the processor and memory buses. It is used to indicate what address in memory or what address on the system bus are to be used in a data transfer operation.
The size of the memory bus also controls the amount of memory that the CPU can address directly.

Memory Bus:-
        The memory bus is used to transfer information between the CPU and main memory(RAM)  in your system. This bus is either a part of the processor bus itself, or in most cases it is implemented separately by a dedicated chipset that is responsible for transferring information between the processor bus and the memory bus.

I/O Bus:-
       All the motherboards have one or more system I/O buses that are used to expand the computer's capabilities. These buses work closely with expansion cards. The slots in the back of the machine are where expansion cards are placed. These slots allow you to expand the capabilities of your machine in many different ways, and the proliferation of both general purpose and very specific expansion cards is part of the success story of the PC platform.

         Most modern PCs have two different types of bus slots. The first is the standard ISA (Industry Standard Architecture) slot; most PCs have 3 or 4 of these. These slots have two connected sections and start about a half-inch from the back of the motherboard, extending to around its middle. This is the oldest  bus type and is used for cards that don't require a lot of speed: for example, sound cards and modems. Older systems may have ISA slots with only a single connector piece on each; these are 8-bit ISA slots and will only support 8-bit ISA cards.