Standard TTL device identification: Which circuit number identifies the IC that contains four two-input AND gates (quad 2-input AND) in the 74xx TTL series?

Introduction / Context:Recognizing common 74xx TTL part numbers is a practical skill in digital electronics. The “quad two-input AND” device is used in countless designs for gating, decoding, and simple combinational logic.

Given Data / Assumptions:

• We refer to classic 74xx TTL numbering.
• We seek the IC that implements four independent 2-input AND gates.

Concept / Approach:Memorize or map the standard codes: 7408 = quad 2-input AND; 7432 = quad 2-input OR; 7404 = hex inverter; 7402 = quad 2-input NOR; 7411 = triple 3-input AND.

Step-by-Step Solution:Check 7408 → known quad 2-input AND → matches.Cross-check others: 7404 (inverters), 7432 (OR), 7402 (NOR), 7411 (3-input AND).Therefore the answer is 7408.

Verification / Alternative check:Any TTL pinout sheet or logic family table confirms these standard functions.

Why Other Options Are Wrong:7402: NOR, not AND.7404: inverters, not AND.7432: OR, not AND.7411: three 3-input ANDs, not four 2-input ANDs.

Common Pitfalls:Confusing 7408 with 7411 (both AND devices but different input counts).

Final Answer:7408