PHYS345 Electricity and Electronics

Answers for 11/4 Assignment

Answer for 13.25

C + D + A.B

Answer for 13.30

. (A+C)

Answer for 13.35

Truth Table for Full Adder:

Ci A B Co S
0 0 0 0 0
0 0 1 0 1
0 1 0 0 1
0 1 1 1 0
1 0 0 0 1
1 0 1 1 0
1 1 0 1 0
1 1 1 1 1

Karnaugh Map for S:       Karnaugh Map for Co:
 AB 00  01  11  10 
Ci\  
 0     0   1   0   1 
 1     1   0   1   0 

Boolean expression

     
 AB 00  01  11  10 
Ci\  
 0     0   0   1   0 
 1     0   1   1   1 

Boolean expression

Logic Gates for Full Adder:

Full Adder Logic

3-Bit Subtractor:

4-Bit Adder

You might also enjoy examining the full subtractor.

Answer for S13.1

A B A' B' A'+B'
0 0 1 1 1
0 1 1 0 1
1 0 0 1 1
1 1 0 0 0

The final column is identical to A NAND B.

Answer for S13.2

Decoder for segment b:

 BA 00  01  11  10 
DC\
 00    1 1 1 1
 01    1 0 1 0
 11    x x x x
 10    1 1 x x

Boxing ones:

 BA 00  01  11  10 
DC\
 00    1 1 1 1
 01    1 0 1 0
 11    x x x x
 10    1 1 x x

Red boxes are represented by C'.

 
 BA 00  01  11  10 
DC\
 00    1 1 1 1
 01    1 0 1 0
 11    x x x x
 10    1 1 x x

Green boxes are represented by A'.B'.

 
 BA 00  01  11  10 
DC\
 00    1 1 1 1
 01    1 0 1 0
 11    x x x x
 10    1 1 x x


Blue boxes are represented by A.B.

 
 BA 00  01  11  10 
DC\
 00    1 1 1 1
 01    1 0 1 0
 11    x x x x
 10    1 1 x x


All boxes are represented by C' + A'.B' + A.B, as shown in the problem statement.


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Last updated Nov. 15, 1999.
Copyright George Watson, Univ. of Delaware, 1999.