Semiconductor Electronics · Question 31

[figure] For the circuit shown above, equivalent GATE is :

1. NOT gate
2. NAND gate
3. AND gate
4. OR gate

Answer

(4) OR gate

Solution

Output of the upper NAND gate: Y1 = A B

Output of the NOR gate: Y2 = A + B

Final NAND gate: Y = Y1 Y2 = Y1 + Y2 (De Morgan)

Y = A B + (A + B)

Y = A + B (absorption: AB + A = A)

the circuit is equivalent to an OR gate.

Answer: (4)