Power semiconductor devices – Match each device class to a typical maximum practical switching frequency List I (Power device) A. Power bipolar transistor B. Power MOSFET C. SCR (thyristor) D. IGBT (insulated-gate bipolar transistor) List II (Typical max frequency order) MHz 100 kHz 10 kHz 1 kHz Select the correct mapping.
-
AA-2, B-1, C-3, D-4
-
BA-3, B-4, C-2, D-1
-
CA-3, B-1, C-4, D-2
-
DA-4, B-1, C-3, D-2
-
EA-1, B-2, C-3, D-4
Answer
Correct Answer: A-3, B-1, C-4, D-2
Explanation
Introduction / Context:In power electronics, device physics limits switching speed. Remembering the rough frequency order helps pick devices for converters, motor drives, and RF power stages.
Given Data / Assumptions:
- Power MOSFETs can reach into the MHz range (low voltage types).
- IGBTs are typically comfortable to tens of kHz (≈100 kHz upper practical bound for fast modules).
- Power BJTs switch slower than MOSFETs, around the 10 kHz order.
- SCRs are the slowest for high-power switching (≈1 kHz order) due to turn-off limitations (unless special commutation).
Concept / Approach:
Map each class to its typical maximum practical switching frequency in power applications: BJT → ~10 kHz; MOSFET → MHz; SCR → ~1 kHz; IGBT → ~100 kHz.
Step-by-Step Solution:
A (Power BJT) → 3 (10 kHz).B (Power MOSFET) → 1 (MHz).C (SCR) → 4 (1 kHz).D (IGBT) → 2 (100 kHz).Verification / Alternative check:
Application notes from device vendors show MOSFETs used at hundreds of kHz to MHz, IGBTs tens of kHz, BJTs slower, and SCRs at line-commutated or low switching frequencies.
Why Other Options Are Wrong:
Swapping MOSFET and SCR contradicts practical converter designs; assigning MHz to IGBTs is atypical.
Common Pitfalls:
Ignoring voltage/current rating dependence on speed; very high-voltage MOSFETs may be slower than low-voltage types.
Final Answer:
A-3, B-1, C-4, D-2.