Thyristor family naming – Match device acronyms to their full names List I (Acronym) A. SUS B. SBS C. SCS D. Shockley diode List II (Device) Silicon unilateral switch Silicon bilateral switch Silicon controlled switch Four-layer diode (p–n–p–n Shockley diode) Select the correct mapping.

Introduction / Context:
Members of the thyristor family include several two- and three-terminal switches. Correctly expanding acronyms avoids confusion during selection and fault analysis.

Given Data / Assumptions:

• SUS = silicon unilateral switch (two-layer-like behavior with triggering).
• SBS = silicon bilateral switch (conducts in both polarities when triggered).
• SCS = silicon controlled switch (gate-controlled four-layer device).
• Shockley diode = four-layer p–n–p–n diode (two-terminal) with negative-resistance region.

Concept / Approach:

Map acronyms to the canonical names used in textbooks and datasheets.

Step-by-Step Solution:

Verification / Alternative check:

Manufacturer datasheets and power electronics texts confirm these expansions.

Why Other Options Are Wrong:

Swapping bilateral/unilateral reverses operating quadrants; mislabeling the Shockley diode ignores its classic four-layer structure.

Common Pitfalls:

Confusing SCS with SCR; the SCR is the silicon controlled rectifier, not “switch.”

Final Answer:

A-1, B-2, C-3, D-4.