Form factor (electronics): Difference between revisions

Revision as of 01:12, 9 January 2013

Revision as of 10:43, 4 February 2013

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{{UnreferencedRefimprove|date=NovemberFebruary 20062013}}

In [[electronics]], the '''form factor''' of an [[alternating current]] waveform (signal) is the ratio of the RMS ([[Root Mean Square]]) value to the [[Average rectified value|average value]] (mathematical mean of [[absolute value]]s of all points on the waveform).<ref>{{cite web|last=Stutz|first=Michael|title=Measurement of AC Magnitude|url=http://www.allaboutcircuits.com/vol_2/chpt_1/3.html|work=BASIC AC THEORY|accessdate=30 May 2012}}</ref> It identifies the ratio of the [[direct current]] of equal power relative to the given alternating current. The former can also be defined as the direct current that will produce equivalent heat.<ref name=Dusza>{{cite book|last=Dusza|first=Jacek|title=Podstawy Miernictwa (Foundations of Measurement)|year=2002|publisher=Wydawnictwo Politechniki Warszawskiej|___location=Warszawa|isbn=83-7207-344-9|pages=323|coauthors=Grażyna Gortat, Antoni Leśniewski|pages=136-142, 197-203|language=Polish}}</ref>

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== Usage ==

Digital AC measuring instruments are often built with specific waveforms in mind. For example, many digital AC multimeters are specifically scaled to display the RMS value of a sine wave. Since the RMS calculation can be difficult to achieve digitally, the absolute average is calculated instead and the result multiplied by the form factor of a sinusoid. This method will give less accurate readings for waveforms other than a sinewave.<ref>{{cite web|last=Tanuwijaya|first=Franky|title=True RMS vs AC Average Rectified Multimeter Readings when a Phase Cutting Speed Control is Used|url=http://www.escoglobal.com/resources/pdf/white-papers/True_G2.pdf|publisher=Esco Micro Pte Ltd|accessdate=2012-12-13/12/12}}</ref>

== Properties ==