If both inputs of a 2-input NOR gate are tied together and driven by the same signal A, what single-function behavior does the device implement?

Difficulty: Easy

Correct Answer: inverter

Explanation:


Introduction / Context:
Gate reconfiguration through tying inputs is a classic technique for reducing parts and creating needed primitives. With NOR and NAND (universal gates), tying inputs can yield inversion, enabling construction of other logic functions.


Given Data / Assumptions:

  • 2-input NOR gate with inputs connected together: A, A.
  • Standard binary logic levels 0 and 1.
  • No additional components assumed.


Concept / Approach:
NOR is NOT(OR). With identical inputs, OR(A, A) equals A. Therefore, NOR(A, A) equals NOT(A). Thus, the tied-input NOR behaves exactly as an inverter. This property is exploited when building universal-gate-only designs: NOT, OR, and AND can all be composed using NOR gates.


Step-by-Step Solution:
1) Start from the NOR definition: Y = NOT(A OR B).2) Tie inputs: B = A, so Y = NOT(A OR A) = NOT(A).3) Conclude that the gate acts as an inverter on signal A.


Verification / Alternative check:
Truth table check: if A = 0, output = 1; if A = 1, output = 0, matching an inverter behavior exactly.


Why Other Options Are Wrong:
“OR gate” is the opposite function before inversion. “AND gate” is unrelated to tying NOR inputs. “any of the above” cannot be true because only one behavior results from the identity OR(A, A) = A.


Common Pitfalls:
Assuming tied inputs average or produce undefined levels; overlooking that OR with identical inputs reduces to the input itself, making NOR a straightforward inverter.


Final Answer:
inverter

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