Computer Science 105 Logic What do AND, OR, and NOT do? What is True and what is False? Preview Questions:

# 2# 2 CS 105 Fall 2006 Boolean Logic Computers don't know anything about True and False They only know 1 and 0. How do we "encode" True and False? We choose 1 as True and 0 as False.

# 3# 3 CS 105 Fall 2006 Using Boolean Logic with a circuit Door Open Keys in Ignition AND BUZZ!!!

# 4# 4 CS 105 Fall 2006 Using Boolean Logic with a circuit Car in Gear Seat Belt Buckled AND NOT BUZZ!!! Yes, it is in gear Buckled input signal is 0 Oops—not buckled!

# 5# 5 CS 105 Fall 2006 Putting it all together Car in Gear Seat Belt Buckled AND BUZZ!!! NOT OR Door Open Keys in Ignition AND

# 6# 6 CS 105 Fall 2006 What does an OR do? OR is not fussy. OR will send a TRUE result if any of its input is TRUE.

# 7# 7 CS 105 Fall 2006 What does AND do? AND will only give a TRUE result (that is, a binary 1) if all input is TRUE.

# 8# 8 CS 105 Fall 2006 What does NOT do? NOT returns the opposite of the input. It only needs one item, not 2, to examine. If the data is True, NOT returns False, and if the data is False, NOT returns True. “The Inverter”

# 9# 9 CS 105 Fall 2006 How many of you do online searching?

# 10 CS 105 Fall 2006 Online Searching How this works with search engines:

# 11 CS 105 Fall 2006 To summarize: What do AND, OR, and NOT do? What is True and what is False?