14.18 Write the truth table for the circuit given in Fig. 14.47 below consisting of NOR gates and identify the logic operation (OR, AND, NOT) which this circuit is performing.
Figure 14.39
(Hint: A = 0, B = 1 then A and B inputs of second NOR gate will be 0 and hence Y=1. Similarly, work out the values of Y for other combinations of A and B. Compare with the truth table of OR, AND, NOT gates and find the correct one.)
Hint: Identify the truth table for the given circuit.
Step 1: Find the output for the given circuit.A and B are the inputs of the given circuit. The output of the first NOR gate is
. It can be observed from the following figure that the inputs of the second NOR gate become the output of the first one.
Hence, the output of the combination is given as:
Step 2: Draw the truth table.The truth table for this operation is given as:
|
A |
B |
Y (=A + B) |
|
0 |
0 |
0 |
|
0 |
1 |
1 |
|
1 |
0 |
1 |
|
1 |
1 |
1 |
This is the truth table of an OR gate. Hence, this circuit functions as an OR gate.
© 2024 GoodEd Technologies Pvt. Ltd.
