Boolean algebra operator symbols In standard Boolean algebra used for digital logic design, which logical operation is represented by the plus sign (+)?
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Ainversion (NOT)
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BAND
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COR
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Dcomplementation of a variable
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Eexclusive-OR (XOR)
Answer
Correct Answer: OR
Explanation
Introduction / Context:Boolean algebra provides a compact symbolic way to describe the behavior of logic circuits. Knowing which symbols correspond to which operations is essential when reading datasheets, simplifying expressions, or designing gate-level implementations.
Given Data / Assumptions:
- The question concerns the conventional symbols used in positive logic Boolean algebra.
- The plus sign (+) appears between Boolean variables (for example, A + B).
- We assume standard textbook conventions (not arithmetic addition).
Concept / Approach:
In Boolean algebra: the plus sign (+) denotes the logical OR operation; the dot (·) or adjacency denotes logical AND; and a bar, prime, or overline denotes logical NOT (inversion). Thus, A + B means A OR B; A · B (or AB) means A AND B; and A' (or Ā) means NOT A.
Step-by-Step Solution:
Identify operator: the symbol in question is +.Recall mapping: + → OR, · → AND, overbar/prime → NOT.Match to option: the only answer naming the OR operation is correct.Verification / Alternative check:
Truth tables confirm that A + B equals 1 when either A or B (or both) are 1, exactly the behavior of an OR gate. This aligns with logic symbols used across 74xx/40xx families and HDL textbooks.
Why Other Options Are Wrong:
- Inversion / complementation uses a bar or prime, not +.
- AND uses a dot or adjacency (AB), not +.
- XOR is typically written as A ⊕ B, not A + B.
Common Pitfalls:
- Confusing arithmetic addition with Boolean OR. In Boolean algebra, 1 + 1 = 1.
- Mixing operator precedence; typically NOT applies first, then AND, then OR.
Final Answer:
OR