2. Motherboard
• Motherboard is the main core of the computer.
• It is also known as Printed Circuit Board (PCB) or circuit board or
System Board.
• It is the main circuit board in which many internal devices such as
video card, sound card, memory, CPU and other devices are
attached.
• None of the other card or devices can work without motherboard.
• Motherboard is a rectangular fiber glass with a printed circuit board
on the surface of which connects one component to another.
• Although the system board's physical structure has changed over
time, its logical structure has remained relatively constant.
• The system board of the personal computer consists of a
microprocessor, supporting circuits, ROM, the system's Primary
Memory units, keyboard interface, timing circuit etc.
2
4. Microprocessor
• Microprocessor is the brain of computer, which does all
the work.
• It is a computer processor that incorporates all the
functions of CPU (Central Processing Unit) on a single
IC (Integrated Circuit) or at the most a few ICs.
• Microprocessors were first introduced in early 1970s.
4004 was the first general purpose microprocessor
used by Intel in building personal computers.
• Arrival of low cost general purpose microprocessors
has been instrumental in development of modern
society the way it has.
4
6. Universal Serial Bus
• It is a high speed serial bus.
• Its data transfer rate is higher than that of a serial port. It
allows interfacing several devices to a single port in a daisy
chain.
• It provides power line along with data lines.
• USB cable contains 4 wires two out of four wires in the USB
cable are used to supply electrical power to devices and
two are reserved for send data and commands.
• It can operate in two modes i.e. Low speed mode and
medium speed mode.
• In low speed mode data transfer rate is 1.5 Mbps and at
medium speed mode data transfer mode is 12 Mbps.
6
