Computer Systems

Week 03 Lesson 01
 Review
 Define volatile and none-volatile
 State what components connect to the North
and South Bridge
 Define what the PSU does?
 What is the name of the PSU socket that
connects to a Hard disk or Optical drive?
 What is the PGA?
 Objectives
 Understand static electricity
 List reasons why we take precautions from
static electricity
 State precautions we can use against static
electricity
 Test anti-static devices
 Define the Motherboards role within a PC
 State the role of a Graphics Card
 Electrostatic Charge

The movement and contact of the human body can

accumulate energy in the form of electrostatic charge
When an electric contact is established, electrostatic
discharge (ESD) takes place in the form of a very brief
flow of current
Although the discharge current is very small, the voltage
could be in the region of few thousand volts
The human body can feel an ESD event if the voltage is
more than 3000 volts
“Electro static discharge (ESD) is the transfer of an
electrostatic charge between two objects. This is a
very rapid event that happens when two objects of
different potentials come into direct contact with
each other. One of the main causes of device failures
in the semiconductor industry is ESD”

NEW VIDEO RESOURCE (BETTER)

Static Electricity: Snap, Crackle, Jump
VG
 Tribo-electrification
 Static electricity must build up a charge greater than
1000 V before we may notice it
 Static Electricity is harmless to humans
 We can withstand up to and including 10,000 V
 Most CPUs, motherboards and associated circuitry
normally operates at +/- 5 V
 An electrical discharge of 10,000 V will blow almost
all computer components
 Electrostatic Charge

ESD is more likely to exist in work places which are

humid, the use of a humidifier can greatly reduce ESD
buildup
Electrical resistance is measured in Ohms
 ESD Symbols
 Fig 1 ESD Susceptibility
Indicates that the
device is
susceptible to ESD
 Fig 2 ESD Protective
Identifies items that
provide ESD
protection
 ESD protective devices
 A range of ESD protective devices are available to protect
the computer from you including
 Wrist Strap
 Elasticised wristband with a metal pad which fits next to the skin
 The cable runs to a ground connector which connects to a earth
 Anti-Static Mat
 Large rubber mat, runs to a ground connector which connects to
earth
 Usually you can connect your wrist band onto the mat
 Anti-Static Bag
 Used to transport and protect computer components
 Newly purchased components are usually supplied in these bags
 Any components not in the chassis of the computer must be kept
in one of these bags
 Working inside a computer
 When working on the internals of a computer you
must…
 Always connect yourself to an electrostatic wristband
and ensure you are earthed
 You should also do this when handling components
outside of the computer and that are not even
connected
 Keep any ‘spare’ components that are not being used
in electrostatic bags
 Never wear a grounding strap when operating a
monitor
 The capacitors hold a huge charge, wearing the strap
offers a shortcut – straight through you to the ground!
 Good uses of ESD
 ESD is used to apply toner to paper in
photocopy machines and laser printers
 ESD is used to clean up the air, removing
pollen and dust to create a healthier
environment
 ESD is used to remove unwanted chemicals
from output from Power Stations
 Electro-Static Damage
•Electrostatic discharge can cause damage to
integrated circuits such as the CMOS and
other memory chips.
•The damage caused by ESD may be instant
failure.
• It is more likely to weaken the chip thus its
lifespan, causing intermittent faults
 Static Electricity Video
Testing for Static Electricity
Electrostatic Charge at a Petrol Station
Pauls guide to ESD
 Follow the safety rules
 Be prepared: have the right tools at hand
 Obey the dress code: nothing dangling that will trap you
 Wear your ESD wrist band
 Before starting, turn off the PC and disconnect the AC
power chord
 Read the manual: do not do things from memory
 Ground yourself by touching the chassis to discharge any
static electricity that has accumulated in your body
 Handle all parts gently, hold components by their edges
 Remember that some components might be too hot to
touch safely
 Take your time and think carefully before acting
This highly magnified
picture shows the
damage that can be
done to an IC by
Electrostatic Discharge
 Anti-static Wrist
Strap

Wrist straps safely remove static charge from

individuals who handle static sensitive
devices
A coiled cord and clip is provided to allow
connection to ground. The ground cord has a
built-in 1M resistor for user safety.
How do you know if its working?
 Anti-static wrist straps can fail to perform
their intended function.
 Ground cords get stressed from prolonged use
and can break open inside the insulation.
 You can't see if your anti-static wrist strap is
performing properly
 They should be tested regularly.
 Electronics professionals should test their wrist
straps for proper function at least once per day
 Testing your wrist band
 Firstly check your multi-meter is working
correctly by setting the 2M-ohms. Have both
probes make contact with each other and record
the reading.
 Now remove the wristband from your antistatic
band and holding one probe at each end test it
 Does it give expected results, if not, why not?
 Why is it important to carryout periodic testing
of anti-static protection devices?
 Don't worry it's only ESD
 What not to do
 Motherboards
The Main Printed Circuit Board Inside The
PC That Contains and Controls The
Components That Are Responsible For
Processing Data.
 Motherboard is…
 Multi-layered printed circuit board
 Copper circuit paths called traces carry signals
and voltages across the motherboard
 Some layers carry data for input/output while
other layers carry voltage and ground returns
 Think of a Motherboard as:
 Futuristic City with many modular plug-in buildings,
using power from a common electrical system
 Multiple-lane highways of various widths
transporting data between buildings
 Data and power infrastructure for the entire computer
 Motherboard
 MD Definition R
esearch Activity
 MD Component i
dentification and
function
 How to install a
motherboard
 Basic Motherboard
Chipset and Functions

Different chips integrated

to a single chip called the
chipset.

The North bridge controls

faster I/P components
likes Graphics and
Memory (RAM)

The south bridge controls

the slower I/O components
like the Serial ports, USB
ports and the IDE.
 Motherboard Determines:
 CPU type and speed  Type of case
 Chipset  ROM
 Types & number of  Plug & Play
connection slots compatibility
 Type of memory  Type of keyboard
 Number of memory
sockets and maximum
memory
 Form Factors
 Form factor means the size and shape of the
actual motherboard
 3 most common Form Factor classifications:
 Baby AT
 ATX

 Slimline NLX
 What other features do modern
Motherboards include?
 In groups spend ten minutes look at recent
motherboard releases
 Consider what additional functionality they
might include
 List a minimum of three components you
could share with the class
Motherboard (Standard ATX Form Factor)

30.5Cm

24.4 cm

12" × 9.6“ (Imperial)

A. Processor (Intel & AMD)
B. North Bridge

"North Bridge: The Intel term for the main portion of the motherboard
chipset that incorporates the interface between the processor and the rest of
the motherboard.
I. South Bridge

"South Bridge: The Intel term for the lower-speed component in the
chipset that has always been a single individual chip.
C. USB Ports
D. PCI Slots (32 Bit)
E. System BIOS (ROM) & CMOS
F. Memory (RAM)
G. Parallel Port (25 pin female D-plug)
H. CMOS Battery
J. Power Connector (24 Pin Molex) P1
K. IDE Connections (4 channels, 2 per slot)
L. ISA Slot (Legacy)
M. Serial Ports
N. Floppy Drive Connector
O. PS/2 Connections for mouse/keyboard
P. AGP Slot (32 bit)
P. AMR Slot
P. Audio inputs/outputs

Mic
Headphone Line out
P. VGA (15 Pin D-Plug Female)
P. Case Pins (PWR, HDD LED, etc…)
P. Newer Motherboards can also include

•SATA (inc E-SATA)

P. Newer Motherboards can also include

•Passive Cooling
P. Newer Motherboards can also include

•Water cooled systems

P. Newer Motherboards can also include

•DDR3 (green slots)

 Video Summary
Form Factors

Installing and configuring motherboards

Specialised Cards – Graphics Card
 What is it?
 A video card is a hardware component whose function is
to generate and output images to a display
 A graphics Card includes multiple sub-components
 Graphics Processing unit (GPU)
 Video BIOS
 Video Memory
 RAMDAC
 Outputs
 Motherboard Interface
 Cooling Devices
 Power Demand
Graphics Processing Unit (GPU)
 A GPU is a dedicated graphics processor optimized
for floating point calculations which are fundamental
to 3D graphics rendering
 The main attributes of the GPU
 Are the core clock rate (typically ranging from
250MHz to 850MHz)
 The number of pipelines (Vertex or Fragment
shaders) used to translate a 3D image into a 2D image
formed by pixels
 Video BIOS
 This contains the basic program that governs the video
card’s operations and provides the instrusions that allow
the computer and software to interface with the card
 It contains information on the memory timing, operating
speeds and voltages of the graphics processor and RAM
and other information
 It is sometimes possible to change the BIOS for higher
performance although is this is typically only done by
card over-clockers as it has the potential of damage to
the card
 Video Memory
 While a Video Card will have its own video memory
called video RAM
 The memory capacity of most modern video cards
range from 128MB to 2GB
 Since video memory needs to be accessed by the
GPU it uses high speed memory
 DDR, DDR2, GDDR3, GDDR4 & GDDR5
 The memory clock rate in modern cards are generally
between 400MHz and 2.4GHz
 Outputs
 There are the connection systems which connects the
displays with the video card
 Some different connection systems are as follows
 Analogue-based standard adopted in the late 1980s designed for
CRT displays, also called VGA connector
 Digital-based standard for displays such as flat-panel displays
and video projectors, these digital based DVI connectors are
used for HDTV
 HDMI is an advanced digital audio/video interconnector released
in 2003 and is commonly used to connect Gaming Consoles and
DVD players to a display
 Display connectors
 Motherboard Interface
 It is the connection system which connects
the graphics card to the motherboard
 Although there are many different
connection systems the main two in use
today are AGP and PCI-Express
 Cooling Device
 Video cards may use a lot of electricity which is
converted into heat
 If the heat isn’t dissipated, the video card could
overheat and get damaged
 Cooling devices are incorporated to transfer the heat
elsewhere
 Power Demand
 Fast Video Cards consume a great deal of power
 Power demands of GPU are mainly greater than that
of CPUs, meaning that the video card may be the
biggest power consumer in the system
 Most connection systems that can be used to connect
a graphics card supply no more than 75watts to power
a graphics card
 For recent graphics cards that require more than this
level of power can connect to a direct PSU power
source
 8 pin (150W) power source
 Advantages of Graphics Cards
 Anti-Aliasing: This is a technique used to counter
distortion caused by aliasing effects
 Motion Blur: Effect used to blur objects moving in
fast motion
 Texture Mapping: Allows the addition of detail on
surfaces, without adding complexity
 Depth of Field: Technique that blurs out of focus
objects
 Lens Flare: Imitation of light sources
 Fresnel Effect: Reflections over an object, depending
on the angle of vision, the greater the angle of vision
the greater the reflection
 Without Graphics Card

Poor Motion Blur & Depth of Field

No reflection detail
(No Fresnel Effect)

Distorted Edges.. No
Poor level of detail anti-Aliasing
 With Graphics Card

Smooth Motion Blur & Depth of field

Car Reflection Detail
turned on. Fresnel Effect

Edge smoothened by
Better level of detail
Anti Aliasing
 Objectives Plenary
 Understand static electricity
 List reasons why we take precautions from
static electricity
 State precautions we can use against static
electricity
 Test anti-static devices
 Define the Motherboards role within a PC
 State the role of a Graphics Card
 Stretch & Challenge
 Download the Electrostatic Discharge Exam
and see what answers you already know and
conduct some research into those you don’t
 ESD Quiz