Demonstrations

Displacement Current

Code Number :	5C20.60
Disclaimer:	Reprinted by permission of Dick Berg, University of Maryland, for use on this website. The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources. Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA. The University of Iowa Disclaimers: U of Iowa Disclaimer All Rights Reserved..
Condition :	Excellent
Principle :	Displacement Current
Area of Study :	Electricity & Magnetism
Equipment :	Amplifiers, speaker, Pasco sensing coil, parallel plate capacitor, wave generator.
Procedure :	Hook the wave generator to an amplifier, and then connect the output of the amplifier to the parallel plate capacitor. Connect the sensing coil to the input of the other amplifier which is connected to a speaker. An amplified frequency of about 50 Hz going into the capacitor works well. Move the sensing coil around the capacitor plates. Notice that the coil only picks up a signal when held in the correct polarized position.

Web Sites

References

Robert J. Sciamanda, "On Maxwell's Displacement Current - I", TPT, Vol. 38, # 6, Sept. 2000, p. 329.

Mark A. Heald, "On Maxwell's Displacement Current - II", TPT, Vol. 38, # 6, Sept. 2000, p. 329.

M. Alonso, E. J. Finn, "On Maxwell's Displacement Current - III", TPT, Vol. 38, # 6, Sept. 2000, p. 329.

A. P. French, "Is Maxwells's Displacement Current a Current?", TPT, Vol. 38, # 5, May 2000, p. 274.

Marcos G. Rizzotto, "Visualizing Displacement Current - A Classroom Experiment", TPT, Vol. 37, # 7, Oct. 1999, p. 398.

N. Gauthier, "A Direct Derivation of the Displacement Current", AJP, Vol. 56, # 10, Oct. 1988, p. 871.

Harold S. Zapotsky, "Does Charge Conservation Imply the Displacement Current", AJP, Vol. 55, # 12, Dec. 1987, p. 1140.

A. J. Dahm, "Calculation of the Displacement Current Using the Integral form of Ampere's Law", AJP, Vol. 46, # 12, Dec. 1978, p. 1227.

W. G. V. Rosser, "Displacement Current in Maxell's Equations", AJP, Vol. 43, # 6, June 1975, p. 502.

Thomas R. Carver, Jan Rajhel, "Direct 'Literal' Demonstration of the Effect of a Displacement Current", AJP, Vol. 42, # 3, March 1974, p. 246.

H. L. Armstrong, "Comment of an Experiment Supposed to Show Displacement Current", AJP, Vol. 33, # 6, June 1965, p. 512.

Hans Meissner, "The Meaning of Experiments Designed to Demonstrate Displacement Current", AJP, Vol. 33, # 6, June 1965, p. 512.

Robert M. Whitmer, "Calculation of Magnetic and Electric Fields from Displacement Currents", AJP, Vol. 33, # 6, June 1965, p. 481.

Mail Questions and Comments to: Dale Stille