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Home » Write the truth table for circuit given in Figure below consisting of NOR gates and identify the logic operation (OR, AND, NOT) which this circuit is performing
Write the truth table for circuit given in Figure below consisting of NOR gates and identify the logic operation (OR, AND, NOT) which this circuit is performing
CBSE | Class 12 | NCERT | Physics | Semiconductor Electronics: Materials, Devices and Simple Circuits
Write the truth table for circuit given in Figure below consisting of NOR 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 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.)

Solution:

Input for the circuit: A and B

For the first circuit, the output is \overline{A+B}

We can see from the diagram that the second gate’s input is automatically the first gate’s output.

Therefore, the output obtained from this combination can be expressed

Y=\overline{\overline{A+B}+\overline{A+B}}=\overline{\bar{A} \cdot \bar{B}}+\overline{\bar{A} \cdot \bar{B}}

=\overline{\bar{A} \cdot \bar{B}}=\overline{\bar{A}}+\overline{\bar{B}}=A+B

Following is the truth table for the given operation:

i

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