The Main Circuit Board

The main circuit board is the central nervous system of the computer. Most of the important components are either mounted on it or connected to it. It is also called the mother-board where the computer's primary electronic circuitry resides. It contains number of electronic components that are essential in the processing and storage operations in computer system. Although main circuit boards are often laid out differently, they all have certain components and circuitry.

  Chips
Integrated circuit chips are used in several different ways in a computer. They are:

1. CPU (microprocessor chip). It is the largest single chip.
2. ROM chips.
3. RAM SIMMs (Single In-line Memory Module) is actually sets of ICs (Integrated circuits) used for random-access memory (RAM). They are mounted on a small connector card similar in appearance to the expansions cards mounted in the expansion slots at the rear of the board.
4. Video display controller chip. They are normally found in expansion card.
5. Disk drive controller chips. They are also normally found in expansion card.
6. Coprocessor chip. In PCs, the coprocessor is a microprocessor support chip that takes over when additional or special processing is needed. The most common uses for the processor are math-intensive and graphic applications. In Intel 80486 series microprocessor (and higher) and Motorola 68040 series microprocessor (and higher) these functions were combined in a single microprocessor chip.

Ports:
A port is a connection from the main circuit to a peripheral by a special cable. Another term for port is interface. There can be various interfaces between hardware, software, and people. In case of port, the interface is hardware to hardware. Ports are arranged along the rear of the main circuit board and provide connection through the back of the system unit. Ports commonly connect the main circuit board to the following:

The Parts of the Computers

(I) Keyboard

(ii) Mouse (or pointing device)

(iii) Monitor

(iv) Printer

(v) External modem (used for communication)

(vi) Joystick (used for games and simulation)

Expansion Slots

Expansion slots are the long plug-in strips in which expansions cards are inserted. Expansion card is a printed circuit with circuitry. They are used to connect the following devices to the main circuit board:

The main Circuit Board

(I) Video monitor

(ii) Disk drive

(iii) Scanner

(iv) External CD-ROM

(v) Internal modem

(vi) Audio

(vii) TV tuner

(viii) Networking

The Bus

Bus is another aspect in the main circuit board. It whisks the electronic bits (0s and 1s) from place to place on specific and predefined routes. A main circuit board’s bus is an electronic pathway between various computer components.

Personal computers have four bus pathways:

(i) The data bus. It sends bits of your data back and forth between the microprocessor and RAM during processing and temporary storage.

(ii) The address bus. This facilitates the assignments of processed data to specific memory locations in RAM.

(iii) The control bus. This carries the microprocessor’s control unit signals from the currently running program to the proper peripherals.

(iv) The expansion bus. This connects the expansion slots to the computer making the expansion cards as an integrated part of the computer.

(v) The local bus. It is often used instead of the expansion bus for operations that require a high -speed data transfer.

Since data are transferred from the computer’s busways, wider bus is better, for, it transfer data faster.

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