For an ideal square wave, the magnitude is constant throughout each half-cycle. Therefore peak value = rms value = average rectified value, making both peak factor and form factor equal to 1. Hence the two factors are equal for a square wave.
Formula / Key Relation
Square wave of amplitude Vm:
Vpeak = Vm
Vrms = Vm
Vavg,rect = Vm
Peak factor = Vpeak/Vrms = 1
Form factor = Vrms/Vavg,rect = 1
Detailed Explanation
Concept & ReasoningPeak factor is V_peak/V_rms, while form factor is V_rms/V_avg(rectified). For a symmetrical square wave of amplitude V_m, the rms value is V_m and the average of the rectified waveform is also V_m. Thus both ratios are exactly 1. Other common waveforms have different rms, average and peak relationships, so their two factors are not equal.How to Solve It in the ExamWrite both definitions before comparing waveform tables.Important Exam PointNever use signed full-cycle average for AC form factor because it would be zero for symmetrical AC.Related Revision PathThis question sits in the revision path Signals and Systems → Waveform…
Concept & Reasoning
Peak factor is V_peak/V_rms, while form factor is V_rms/V_avg(rectified). For a symmetrical square wave of amplitude V_m, the rms value is V_m and the average of the rectified waveform is also V_m. Thus both ratios are exactly 1. Other common waveforms have different rms, average and peak relationships, so their two factors are not equal.
How to Solve It in the Exam
Write both definitions before comparing waveform tables.
Important Exam Point
Never use signed full-cycle average for AC form factor because it would be zero for symmetrical AC.
Related Revision Path
This question sits in the revision path Signals and Systems → Waveform Parameters → Form Factor .
Quick Trick
Write both definitions before comparing waveform tables.
Common Mistake
Assuming form factor and peak factor are the same definition.
Exam Tip
Never use signed full-cycle average for AC form factor because it would be zero for symmetrical AC.
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