ENGG 1015 Tutorial
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Introduction to Electrical and Electronic
Engineering – 2012 Fall Semester
Time and Venue
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Tutor
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Class: 1430-1520 P4, every other Monday
Leon LEI (me): CB 806
Contact me and TAs via Piazza
Tutorial materials
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http://www.eee.hku.hk/~culei/ENGG1015.html
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ENGG 1015 Tutorial
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Each class: 40 min. tutorial + 10 min. Q/A
Tutorial materials
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Regular tutorials
Revision tutorial before examination (Tentatively)
Question banks
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Homework 2011, 2010 (may be obsolete)
Past paper 2011, 2010 (may be obsolete)
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ENGG 1015 Tutorial
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Lecture/Lab materials, announcements  Course site
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Moodle  HKU Computer Center
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https://piazza.com/class#fall2012/engg1015
Admin help  Piazza (Private post)
Extra lab check-off session  TA office hour (CB LG205)
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http://www.its.hku.hk/lms/moodle/v2/support_student.php,
eLearningTeam@hku.hk, 2859 2480
Prompt learning materials help, peer learning  Piazza
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http://www.eee.hku.hk/~engg1015/fa12/index.html
Tue 1530, Tue 1630, Fri 1430, Fri 1530
Textbook  No textbook
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ENGG 1015 Tutorial
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Systems and Digital Circuits (I)
24 Sept
Learning Objectives
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Identify concepts of systems
Converts between three representations of digital
logic
News
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Start to have laboratory sessions this week
(Suggest to bring your laptop)
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Question 1: Top-down vs Bottom-up
Item
Driven by system requirement
Top-down
Bottom-up
Yes
Driven by component integration
Yes
Construct system by composing smaller parts
Yes
Construct system by decomposing
Yes
Generate new ideas from system requirements
Yes
Synthesize new ideas from existing components
Must work with unknown system components as
black-boxes
Yes
Yes
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Question 2: Procedures in top-down
and bottom-up
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Making a dinner (Top-down)
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Decide the types of dishes according to the location, number of
people, time and purpose of dinner
Design dishes according to the types of dishes, diet
requirements, kitchen equipment
Find out required ingredients and
sauces for each decided dishes
Get all things ready
(e.g. buy and clean ingredients,
prepare sauces)
Cook every dishes
Bring dishes to the table
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Question 2: Procedures in top-down
and bottom-up
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Making a dinner (Bottom-up)
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Find out the ingredients available
Clean and cut the ingredients according to your own skill and
available kitchen equipment
Mix and match available ingredients as different dishes to meet
the dinner requirements, such as dietary requirements, location,
number of people, time and purpose of dinner, etc.
Cook every dishes by the given kitchen equipment
Bring dishes to the table
Making a Rube Goldberg Machine?
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Question 2: Procedures in top-down
and bottom-up
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Making a Rube Goldberg Machine (Top-down)
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Decide the types of stages according to the location, number of
stages, and interface of each stage
Design stages according to the types of stages, input and output
requirements
Find out the required components for each stage
Get all things ready (e.g. acquire from the TA and technician)
Prepare and assemble each stage
Combine each stage together
Fine-tune the connection between stages
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Question 2: Procedures in top-down
and bottom-up
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Making a Rube Goldberg Machine (Bottom-up)
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Find out the components available
Mix and match available components as different stages to meet
the project requirements such as types of stages according to the
location, number of stages, and interface of each stage etc.
Prepare and assemble each stage by the given equipment
Combine each stage together
Fine-tune the connection between stages
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Quick quiz 1
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What is the only set of input conditions
that will produce a LOW output for any
OR gate?
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Any one of the input is LOW
Any one of the input is HIGH
All inputs are LOW
All inputs are HIGH
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Quick quiz 2
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What is the only input combination that
will produce a HIGH at the output of a
five-input AND gate?
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Any one of the input is LOW
Any one of the input is HIGH
All inputs are LOW
All inputs are HIGH
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Quick quiz 3
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What logic level should be applied to
the second input of a two-input AND
gate if the logic signal at the first input is
to be inhibited (prevented) from
reaching the output?
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A LOW input will keep the output LOW
A LOW input will keep the output HIGH
A HIGH input will keep the output LOW
A HIGH input will keep the output HIGH
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Representing logic operations
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Each function can be represented
equivalently in 3 ways:
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Truth table
Boolean logic expression
Schematics
Truth Table
Schematics
1st semester, 2011
Digital Logic - ENGG1015 - K. Wong
Boolean
Expression
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Conversion of three representations
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Truth table
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Boolean expression
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Try every 0/1 combinations of every input
variables
Simplification (Next tutorial)
Logic circuit
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From Boolean expression
Using AND/OR/NOT gates
Alternative: Bottom-up approach
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Conversion between NOT, AND, OR,
NAND
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Bottom-up: Construct NOT gate, AND gate and OR
gate from NAND gate
i) 1
0
1
0
iii)
ii)
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Question 3: From logic equations
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For the expression x  AB  C  D  , construct the
corresponding logic circuit, using only AND, OR gates
and INVERTERs (NOT gate).
AB  C  D   AB  C  D   AB  C  D 
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Draw the circuit diagram to implement the expression
X  (A  B)(B  C)
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Draw the circuit diagram that implements the expression
x  ABC ( A  D) using gates having no more than three
inputs.
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Question 3: From logic equations
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Boolean expressions
 Truth table and logic circuit (AND/OR/NOT)
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Question 3: From logic equations
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Boolean expressions
 Truth table and logic circuit
(AND/OR/NOT)
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Question 4: From truth tables
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Derive the Boolean expression
of the output x in terms of the
input
Construct the logic circuit using
AND gates, OR gates, and
INVERTERs.
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Solution 4
x  ABC  ABC  ABC  ABC

 
 
 AC  B  B   AB  C  C   BC  A  A 
 ABC  ABC  ABC  ABC  ABC  ABC

 AC  AB  BC
1. Construct A/B/C
2. Construct not A/B/C
3. Construct AND gates
4. Construct OR gate
1
2
3
4
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Question 4: From truth tables
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Truth table  Boolean expressions and logic
circuit
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Determining output level from a diagram
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Question 5: From logic circuits
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Question 5: From logic circuits
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Quick quiz 4
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What is the output expression of the following logiccircuit diagram?
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x  D   A  BC  E
x   D  A  BC   E
x   D  A  B  C   E
x  D   A  B C   E


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Quick checking
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True or false
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An AND gate output will always differ from an OR gate
output for the same input conditions.
False
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Lecture: http://www.eee.hku.hk/~engg1015/
Tutorial: http://www.eee.hku.hk/~culei/ENGG1015.html
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