CPI LAB FILE 2014 RAJESH KUMAR | 12LCS003 1 Practical-1 Objective: To study the components of a motherboard. Motherboard The motherboard is one of the most important parts of the PC. A computer has many components, each with their own roles and functions. The role of the motherboard is to allow all these components to communicate with each other. Fig 1.1 Mother board Components of a motherboard: Processor Socket: The processor socket is the central piece of a motherboard, usually being located near the center of the motherboard. It’s also the central piece because it holds the processor – the brain of your computer. socket or CPU slot is a mechanical component(s) that provides mechanical and electrical connections between a microprocessor and a printed circuit board (PCB). This allows the CPU to be replaced without soldering. A CPU socket is made of plastic, a lever or latch, and metal contacts for each of the pins or lands on the CPU. Many packages are keyed to ensure the proper insertion of the CPU. CPUs with a PGA (pin gridarray) package are inserted into the socket and the latch is closed.
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CPI LAB FILE 2014
RAJESH KUMAR | 12LCS003 1
Practical-1
Objective: To study the components of a motherboard.
Motherboard
The motherboard is one of the most important parts of the PC. A computer has many components, each
with their own roles and functions. The role of the motherboard is to allow all these components to
communicate with each other.
Fig 1.1 Mother board
Components of a motherboard:
Processor Socket:
The processor socket is the central piece of a motherboard, usually being located near the center of the
motherboard. It’s also the central piece because it holds the processor – the brain of your computer. socket
or CPU slot is a mechanical component(s) that provides mechanical and electrical connections between a
microprocessor and a printed circuit board (PCB). This allows the CPU to be replaced without soldering.
A CPU socket is made of plastic, a lever or latch, and metal contacts for each of the pins or lands on the
CPU. Many packages are keyed to ensure the proper insertion of the CPU. CPUs with a PGA (pin
gridarray) package are inserted into the socket and the latch is closed.
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Fig 1.2 Processor
Expansion Slots
Expansions have the role of letting you install additional components to enhance or expand the
functionality of your PC. You can install a TV tuner, a video capture card, a better soundcard, etc. – you
get the idea. These ports are located under the video card slot, and come in the form of PCI slots (on older
motherboards) or a scaled-down version of PCI-Express slots (on newer motherboards). Some
motherboards come with both types of expansion slots. The number of slots is usually dependent on the
format of the motherboard .
Fig 1.3 PCI slots
IDE and SATA Ports
IDE and SATA ports are used to provide connectivity for the storage devices and optical drives. The IDE
interface is somewhat outdated. It was replaced by the smaller and much faster SATA interface, which
currently reached its 3rd revision, being able to achieve maximum speeds of up to 600 MB/s, as opposed to
the IDE interface, which can reach a maximum of 133 MB/s.
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Fig 1.4 IDE slots
BIOS Chip and Battery
The BIOS chip contains the basic code needed to take your computer through the boot process, up to the
point where the operating system takes over. Since the BIOS code is stored on a memory chip that needs
constant power to function, a battery is also present to keep the chip powered when the computer is
unplugged.
Fig1.5 Battery
Northbridge and Southbridge
North Bridge: -The north bridge is an integrated circuit that is responsible for communications between
the CPU interface, AGP, and the memory. The north bridge is a single-chip that is north of the PCI bus
however, early computers may have had up to three separate chips that made up the north bridge. The north
bridge, which has a large heat sink attached to it. It gets hot because of the often very large amounts of data
traffic which pass through it. All around the north bridge you can see the devices it connects. The north
bridge and its immediate surround dings. A lot of traffic runs through the north bridge, hence the heat sink.
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FIG-1.6 (NORTH BRIDGE AND SOUTH BRIDGE)
South Bridge: - The south bridge is a chip that connects to other components inside computer through
bridge. The function of the south bridge is to send and receive computer data and controls input and output
devices. South bridge multitasks and performs all the functions. Southbridge is a reference to a chipset on a
PC motherboard. It is a group of microchips designed for a single function and manufactured as a single
unit.
Fig 1.7 North Bridge
Fig 1.8 South Bridge
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Practical – 2
Objective: To study the components of Switch Mode Power Supply
(SMPS).
Components of Switch Mode Power Supply:
Switch Mode Transistors and other Semiconductors:
A transistor is small and fast semiconductor used for amplification and voltage stabilization. Bipolar Power
Transistors (often BU or 2SC/2SD numbers)- High voltage power transistor, which is used as the main
switch Mode transistor.
Diodes and Rectifiers: AC line rectifier uses a combination of 2 or 4 diodes. High efficiency diodes are
used to rectify output voltages.
Capacitors (filter and bypass) in SWITCH MODE POWER SUPPLY (SMPS):
Filter Capacitors - Used to filter the rectified AC line input voltage and various outputs of the power supply.
Bypass Capacitors - These are green colored, high quality plastic dipped or rectangular molded capacitors
part of RFI filter. They are placed at output section and seldom fail.
Resistors: Test for proper value with the help of multi meter. While measuring the resistor in-circuit, if the
value is higher than normal value, then resistor is bad.
Fig 2.1 Components of SMPS
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Transformers and Inductors required in a SWITCH MODE POWER SUPPLY (SMPS)
High Frequency Transformers - They consist of the switch Mode power transformer and feedback
transformer. They provide line isolation and generate multiple output voltage. They rarely cause problems
and can be tested for open circuit. Some supplies use small Transformers for feedback instead of
optoisolators. Optoisolator is used to isolate the input line with the rest of the section.
Inductors - Output inductors rarely fail and they can be tested for open circuit. Replace the faulty inductor if
found.
Coupled Inductors - They are used as a part of Pi type RFI filter which is placed in the AC input circuit. The
windings of inductor are in series with AC line. They look like small transformer. They are very reliable and
help to reduce noise and spikes. They can be tested for open circuit.
Fig 2.2 Outer view of SMPS
.
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Practical – 3
Objective: To study the various ports and cables.
Computer Ports:
Computer ports are connection points or interfaces with other peripheral devices. There are two main types
of computer ports: physical and virtual.
Types of ports:
Physical ports are used for connecting a computer trough a cable and a socket to a peripheral device.
Physical computer ports list includes serial ports (DB9 socket ), USB ports ( USB 2.0 or 3.0 socket /