Computer Science 129
Science, Computing and Society
Week 5
Chapter 4
GRE/GMAT WORDS
• Assuage – to lessen (pain, grief, guilt)
• Anomaly – something irregular or
abnormal
• Propriety – conformity to established
standards of behavior, manner etc.
• Enigma – puzzling person, event or
situation
Chapter 4
• Logic Gates
• an idealized or physical device
implementing a Boolean function, that is, it
performs a logical operation on one or
more logic inputs and produces a single
logic output.
Chapter 4
• Boolean Function
• 1854 mathematician George Boole
• BOOK - An Investigation of the Laws of
Thought
• Algorithms – If – Then statements
Chapter 4
• AND Logic Gate
• If input A AND input B are
A 1, then output is 1
INPUT
OUTPUT
A
B
A AND B
0
0
0
0
1
0
1
0
0
1
1
1
Chapter 4
• OR Logic Gate
• If input A or input B
are a 1, then output is
a1
INPUT
OUTPUT
A
B
A OR B
0
0
0
0
1
1
1
0
1
1
1
1
Chapter 4
• NOT Logic Gate
• Output is opposite of
input
• If input A is 1, then
output is 0
• If input A is 0, then
output is 1
INPUT
OUTPUT
A
NOT A
0
1
1
0
Chapter 4
• NOR Logic Gate
• If input A nor input B
are a 1, then output is
a1
INPUT
OUTPUT
A
B
A NOR B
0
0
1
0
1
0
1
0
0
1
1
0
What You Should Know
• KNOW ALL GRE/GMAT WORDS FOR
MIDTERM EXAM
What You Should Know
• Be able to define all 4 Logic Gates
discussed
• Know the outputs for each type