Logic family fundamentals: “Transistor–Transistor Logic (TTL) uses the bipolar junction transistor as its primary circuit element.” Decide whether this is accurate.

Introduction / Context:
Several digital logic families exist, each anchored by a particular device technology. TTL and CMOS are the two most common classical families. This question probes recognition of TTL’s underlying device.

Given Data / Assumptions:

• TTL standard logic family (74xx, 74LSxx, etc.).
• Bipolar junction transistors (BJTs) versus MOSFETs.
• Typical 5 V logic supplies.

Concept / Approach:
TTL stands for Transistor–Transistor Logic. The basic gates use multi-emitter bipolar transistors in the input stage, saturating transistors, and totem-pole BJT outputs. By contrast, CMOS logic uses MOSFETs as the main switching devices. Therefore, stating that TTL’s main circuit element is the bipolar transistor is correct.

Step-by-Step Solution:

Verification / Alternative check:
Datasheets and textbooks for 74LS/74ALS/74F series depict bipolar transistor stages throughout the logic path.

Why Other Options Are Wrong:
Incorrect: would contradict the very definition and construction of TTL.

Common Pitfalls:
Confusing “TTL logic levels” (input/output voltage specs) with internal device technology; some CMOS families are “TTL-compatible” but still use MOSFETs internally.

Final Answer:
Correct