LESSON 02 – SUM OF PRODUCTS EQUATION

LESSON WORK

QUESTION 1

Consider the following truth tables and give the corresponding sum of products equations.

a)

A	B	Q
0	0	0
0	1	1
1	0	0
1	1	1

b)

A	B	C	Q
0	0	0	1
0	0	1	1
0	1	0	0
0	1	1	0
1	0	0	1
1	0	1	0
1	1	0	1
1	1	1	0

QUESTION 2

You have been hired by Dr. Evil to create a circuit that will control the launch of nuclear missiles. The circuit has four inputs:

• D for Dr Evil
• G for Guard 1
• H for Guard 2
• S for Safety

It has one output:

• L for Launch

The circuit needs to be designed such that output L is ON only when:

• The safety (S) is OFF and Dr. Evil (D) is pressing down his button.
  
  
• The safety (S) is OFF and both guards (G & H) are pressing their button.
  
  
• The safety (S) is ON and Dr. Evil (D) and both guards (G & H) are pressing their button.

Create a circuit by:

a) Create the truth table with inputs D, G, H & S and output L. You may wish to only include the rows that have the output L equal to 1.

b) Generate an SOP equation.

c) Draw the circuit diagram.