NEET-XII-Physics
14: Semiconductor Electronics: Materials Devices and Simple Circuits
- #18Write the truth table for circuit given in Fig. 14.47 below consisting of N OR gates and identify the logic operation
( OR , AND, NOT) which this circuit is performing.
(Hint: A = 0, B = 1 then A and B inputs of second N OR 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.)
Ans : A and B are the inputs of the given circuit. The output of the first N OR
gate is.gif)
. It can be observed from the following figure that the inputs of the second N
OR
gate become the out put of the first one.
Hence, the output of the combination is given as:
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.