SMPS units are compact and relatively tolerant of input-voltage variation, but their switching action can inject high-frequency ripple/noise and electromagnetic interference. Therefore 'SMPS has low input ripple' is the incorrect statement among the given choices.
Formula / Key Relation
Switching loss/EMI are controlled using high-frequency filters and layout.
SMPS size ∝ inverse of practical switching frequency for magnetics, broadly.
Detailed Explanation
Concept & ReasoningA switched-mode supply operates semiconductor devices at high frequency, allowing smaller magnetic components and high efficiency. Regulation can tolerate a wide input range. The same fast switching edges, however, create conducted and radiated EMI, so input/output filters are important. The question asks for the incorrect characteristic, so the ripple/noise statement must be read carefully.How to Solve It in the ExamSMPS advantages: compact, efficient, regulated; drawback: EMI/switching noise.Important Exam PointWatch the word 'incorrect' before selecting an attractive advantage.Related Revision PathThis question sits in the revision path Power Electronics → Switched Mode Power Supplies → SMPS Characteristics .
Concept & Reasoning
A switched-mode supply operates semiconductor devices at high frequency, allowing smaller magnetic components and high efficiency. Regulation can tolerate a wide input range. The same fast switching edges, however, create conducted and radiated EMI, so input/output filters are important. The question asks for the incorrect characteristic, so the ripple/noise statement must be read carefully.
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