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A Simple Demonstration of the Power Factor

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2013 ASEE Annual Conference & Exposition


Atlanta, Georgia

Publication Date

June 23, 2013

Start Date

June 23, 2013

End Date

June 26, 2013



Conference Session

Innovations in Teaching and Research in Physics or Engineering Physics II

Tagged Division

Engineering Physics & Physics

Page Count


Page Numbers

23.103.1 - 23.103.7



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Paper Authors

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Robert A Ross University of Detroit Mercy

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A Simple Demonstration of the Power FactorThe power factor is a useful topic covered as part of the curriculum on alternating currentcircuits. The first exposure is typically in introductory courses. It is revisited in upper levelnetwork theory or circuit analysis courses in physics and engineering. It is standard practice toinclude the power factor in the curriculum of the circuits courses taught to all engineers.While the power factor is simply the cosine of the phase angle between the voltage and current, ithas practical application for circuits containing reactive loads. Working scientists and engineersare concerned about the power factor in a broad variety of contexts ranging fromelectromechanical systems, e.g. motors, to impedance matching networks in audio and broadcastsystems. The power company cares about a user’s power factor and sets rates accordingly.We have developed a simple demonstration of an alternating current circuit using electric lampsfor resistive loads. The demonstration can easily be adapted to a laboratory experiment in eithera second semester general physics course or a more advanced laboratory course on circuits. Thepedagogical value of the activity is two-fold, it provides a clear visual representation of thepower factor and it serves as a springboard for further discussion of the nature of the phaserelationship of reactive circuit elements. Details of the demonstration and the laboratoryexperiment are provided.

Ross, R. A. (2013, June), A Simple Demonstration of the Power Factor Paper presented at 2013 ASEE Annual Conference & Exposition, Atlanta, Georgia. 10.18260/1-2--19117

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