According to standard Poynting vector arguments, energy in a circuit flows from the batteries to the resistors, not through the connecting wires, but through empty space between the wires. The computer simulation CircuitSurveyor helps to visualize this counterintuitive fact. The simulation also demonstrates the electric fields present near a circuit.
REFERENCES
1.
D. J.
Griffiths
, Introduction to Electrodynamics
, 3rd ed. (Prentice Hall
, Upper Saddle River, NJ
, 1999
), pp. 346
–349
.2.
Reference 1, p. 96.
3.
R. P.
Feynman
, R. B.
Leighton
, and M.
Sands
, The Feynman Lectures on Physics
, (Addison-Wesley
, Reading, MA
, 1964
), Vol. II
, pp. 17
–6
and
–27
.4.
S.
Majcen
, R. K.
Haaland
, and S. C.
Dudley
, “The Poynting vector and power in a simple circuit
,” Am. J. Phys.
68
, 857
–859
(2000
).5.
See supplementary material at http://dx.doi.org/10.1119/1.3679838 to download the program, which can also be run or downloaded from www.oberlin.edu/physics/dstyer/CircuitSurveyor. The Java source code and executable are freely available and are released under the terms of the GNU General Public License, version 3. The program runs under Java SE 6 (version 1.6) or higher, and is distributed without warranty. To use it locally, download CircuitSurveyor.zip and unzip it into any directory, for example, into MyPhysicsPrograms/EMPrograms/CircuitSurveyor. Use a text editor to change the phrase http://www.oberlin.edu/physics/dstyer/CircuitSurveyor/in LaunchCircuitSurveyor.jnlp to, for example, file://MyPhysicsPrograms/EMPrograms/CircuitSurveyor/. Then double click on the edited file LaunchCircuitSurveyor.jnlp.
6.
M. A.
Heald
, “Electric fields and charges in elementary circuits
,” Am. J. Phys.
52
, 522
–526
(1984
).7.
J. D.
Jackson
, “Surface charges on circuit wires and resistors play three roles
,” Am. J. Phys.
64
, 855
–870
(1996
).8.
N. W.
Preyer
, “Surface charges and fields of simple circuits
,” Am. J. Phys.
68
, 1002
–1006
(2000
).9.
I.
Galilia
and E.
Goihbarg
, “Energy transfer in electrical circuits: A qualitative account
,” Am. J. Phys.
73
, 141
–144
(2005
).10.
M. K.
Harbola
, “Energy flow from a battery to other circuit elements: Role of surface charges
,” Am. J. Phys.
78
, 1203
–1206
(2010
).11.
R.
Jacobs
, A.
de Salazar
, and A.
Nassar
, “New experimental method of visualizing the electric field due to surface charges on circuit elements
,” Am. J. Phys.
78
, 1432
–1433
(2010
).12.
R.
Chabay
and B.
Sherwood
, Matter and Interactions
, 3rd ed. (John Wiley & Sons
, New York
, 2011
), Vol. II
, Chap. 19.13.
R. V.
Southwell
, Relaxation Methods in Theoretical Physics
(Oxford University Press
, Oxford, UK
, 1946
); andD. A.
Hastings
, “Computational method for electrical potential and other field problems
,” Am. J. Phys.
43
, 518
–524
(1975
).© 2012 American Association of Physics Teachers.
2012
American Association of Physics Teachers
AAPT members receive access to the American Journal of Physics and The Physics Teacher as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.
