Logic families — which one uses bipolar junction transistors (BJTs) internally? Identify the logic family composed of bipolar junction transistors.

Introduction / Context:
Digital ICs are built using different device technologies. Two major families historically are TTL and CMOS. Knowing which devices they are based on helps predict speed, power, and interface behavior.

Given Data / Assumptions:

• TTL stands for Transistor-Transistor Logic.
• CMOS stands for Complementary Metal-Oxide-Semiconductor.
• DIP is a package type, not a logic family.

Concept / Approach:
TTL uses multiple-emitter BJTs and associated structures to implement logic gates. CMOS uses complementary MOSFET pairs (pMOS and nMOS). Therefore, if asked which logic family is composed of BJTs, the correct choice is TTL.

Step-by-Step Solution:
Match family names to device types: TTL → BJTs, CMOS → MOSFETs.Exclude non-families: DIP is a packaging form factor, not technology.Select TTL as the BJT-based family.

Verification / Alternative check:
Any TTL datasheet (74xx series) shows bipolar transistor schematics; classic 74LS, 74H, 74F families are all bipolar implementations.

Why Other Options Are Wrong:

• CMOS: built with MOSFETs, not BJTs.
• DIP: Dual In-line Package is packaging only.
• BJT: a device type, not a standardized logic family.

Common Pitfalls:

• Confusing the logic family name with the device type or package.
• Assuming all modern logic is CMOS; classic TTL remains widely referenced.

Final Answer:
TTL