LESSON 03 – LOGIC GATES (NAND & NOR) & EQUIVALENT CIRCUITS

LESSON NOTE 2 - EQUIVALENT CIRCUITS

• There are usually many ways to create a circuit with a specific functionality. Specialists in this field work to find the simplest circuit possible.
  
  
• We can tell two circuits are equivalent by seeing if their logic tables are the same.
  
  
• Example: Consider the following circuit diagram for a NAND gate:

This circuit will have the following logic table:

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

Now consider the following circuit diagram:

The logic tables for the above diagram will look like this. (Note that extra columns were added simply to make the calculation of Q easier.)

A	B	Not(A)	Not(B)	Q
0	0	1	1	1
0	1	1	0	1
1	0	0	1	1
1	1	0	0	0

Now we compare the input and output columns of the logic tables. They are the same. Therefore, both circuits are the equivalent.