Digital logic families: A type of integrated-circuit digital logic technology that uses bipolar junction transistors (BJTs) is known as ________.

Introduction / Context:
Logic families are categorized by the underlying transistor technology, which affects speed, power consumption, noise margins, and interfacing. Recognizing which families use BJTs versus MOSFETs is fundamental.

Given Data / Assumptions:

• TTL stands for transistor-transistor logic.
• CMOS uses complementary MOSFETs.
• NMOS refers to n-channel MOS technology.
• LSI describes integration scale, not a logic family per se.
• ECL (emitter-coupled logic) also uses BJTs but is a distinct high-speed family; the common textbook answer contrasting MOS is TTL.

Concept / Approach:
Identify which option explicitly names a BJT-based family in contrast to MOS-based families. TTL is the canonical BJT logic family in general-purpose digital design.

Step-by-Step Solution:
List families: TTL (BJT), CMOS (MOSFET), NMOS (MOSFET), LSI (integration level), ECL (BJT but niche).Select most representative BJT-based general family → TTL.

Verification / Alternative check:
Datasheets for 74xx series identify TTL as BJT based, whereas 74HC/74HCT are CMOS based.

Why Other Options Are Wrong:
CMOS/NMOS: MOSFET technologies, not BJT.LSI: describes density, not device type.ECL: also BJT but specialized; the course-level contrast usually expects TTL as the standard BJT logic family.

Common Pitfalls:
Confusing integration scale (SSI/MSI/LSI) with technology, or assuming all modern logic is MOS-only.

Final Answer:
TTL