AND logic gate behavior In digital electronics, under what input condition(s) will a multi-input AND gate produce a HIGH (logic 1) at its output?

Introduction / Context:
An AND gate is one of the fundamental combinational logic elements used in digital systems, microcontrollers, and FPGA designs. Knowing precisely when its output goes HIGH is essential for designing control logic, enabling conditions, and safety interlocks.

Given Data / Assumptions:

• Standard positive logic convention is used (HIGH = logic 1, LOW = logic 0).
• The gate may have two or more inputs.
• Ideal logic levels with sufficient noise margins.

Concept / Approach:
The truth table of an AND function is defined by the Boolean expression Y = A * B * C * …, where * denotes the logical AND operation. The product of logic variables equals 1 only if every factor equals 1. Hence, the AND gate outputs a 1 precisely when every input is 1.

Step-by-Step Solution:
Define the function: Y = A1 * A2 * … * An.Evaluate case when any input is 0: since 0 * X = 0, the output is 0.Evaluate case when all inputs are 1: since 1 * 1 * … * 1 = 1, the output is 1.Therefore, a HIGH output occurs only when all inputs are HIGH.

Verification / Alternative check:
Construct a truth table for a 3-input AND gate and observe that the sole HIGH output row is A = 1, B = 1, C = 1. Karnaugh mapping also yields a single minterm representing the all-ones input.

Why Other Options Are Wrong:
At least one input is HIGH: describes OR behavior, not AND.At least one input is LOW: this guarantees a LOW output for AND, not HIGH.All inputs are LOW: AND of zeros is zero.

Common Pitfalls:
Confusing AND with OR, or mixing negative logic conventions. Also, assuming a floating input acts like a logic 1—floating inputs must be properly biased; otherwise, output can be unpredictable.

Final Answer:
All inputs are HIGH.