PPT

1. Simple digital
circuit
1

2. AND Function
Output Y is TRUE if inputs A AND B are
TRUE, else it is FALSE.
Logic Symbol 
Text Description 
Truth Table 
Boolean Expression 
AND
A
B
Y
INPUTS OUTPUT
A B Y
0 0 0
0 1 0
1 0 0
1 1 1
AND Gate Truth Table
Y = A x B = A • B = AB
AND Symbol
2

3. OR Function
Output Y is TRUE if input A OR B is
TRUE, else it is FALSE.
Logic Symbol 
Text Description 
Truth Table 
Boolean Expression  Y = A + B
OR Symbol
A
B
YOR
INPUTS OUTPUT
A B Y
0 0 0
0 1 1
1 0 1
1 1 1
OR Gate Truth Table
3

4. Draw the symbol for logic
1
3
2
4

5. NOT Function (inverter)
Output Y is TRUE if input A is FALSE,
else it is FALSE. Y is the inverse of A.
Logic Symbol 
Text Description 
Truth Table 
Boolean Expression 
INPUT OUTPUT
A Y
0 1
1 0
NOT Gate Truth Table
A YNOT
NOT
Bar
Y = A
Y = A’
Alternative Notation
Y = !A
5

6. NAND Function
Output Y is FALSE if inputs A AND B
are TRUE, else it is TRUE.
Logic Symbol 
Text Description 
Truth Table 
Boolean Expression 
A
B
YNAND
A bubble is an inverter
This is an AND Gate with an inverted output
Y = A x B = AB
INPUTS OUTPUT
A B Y
0 0 1
0 1 1
1 0 1
1 1 0
NAND Gate Truth Table
6

7. NOR Function
Output Y is FALSE if input A OR B is
TRUE, else it is TRUE.
Logic Symbol 
Text Description 
Truth Table 
Boolean Expression  Y = A + B
A
B
YNOR
A bubble is an inverter.
This is an OR Gate with its output inverted.
INPUTS OUTPUT
A B Y
0 0 1
0 1 0
1 0 0
1 1 0
NOR Gate Truth Table
7

8. Individual work
8

9. Circuit-to-Truth Table Example
OR
A
Y
NOT
AND
B
C
AND
2# of Inputs = # of Combinations
2 3 = 8
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
A B C Y
9

10. Circuit-to-Truth Table Example
OR
A
Y
NOT
AND
B
C
AND
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
A B C Y
0
0
0
0
1
0
0
0
10

11. Circuit-to-Truth Table Example
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
A B C Y
0
OR
A
Y
NOT
AND
B
C
AND
0
0
1
0
1
1
1
1
11

12. Circuit-to-Truth Table Example
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
A B C Y
0
1
0
OR
A
Y
NOT
AND
B
C
AND
0
1
0
0
1
0
0
0
12

13. Circuit-to-Truth Table Example
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
A B C Y
0
1
0
0
OR
A
Y
NOT
AND
B
C
AND
0
1
1
0
1
1
1
1
13

14. Circuit-to-Truth Table Example
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
A B C Y
0
1
0
1
0
OR
A
Y
NOT
AND
B
C
AND
1
0
0
0
0
0
0
0
14

15. Circuit-to-Truth Table Example
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
A B C Y
0
1
0
1
0
0
OR
A
Y
NOT
AND
B
C
AND
1
0
1
0
0
0
0
0
15

16. Circuit-to-Truth Table Example
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
A B C Y
0
1
0
1
0
0
0
OR
A
Y
NOT
AND
B
C
AND
1
1
0
1
0
0
1
1
16

17. Circuit-to-Truth Table Example
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
A B C Y
0
1
0
1
0
0
1
0
OR
A
Y
NOT
AND
B
C
AND
1
1
1
1
0
0
1
1 17

18. Group work
18

19. 19