The magnetic pickup of an electric guitar uses electromagnetic induction to convert the motion of a ferromagnetic guitar string to an electrical signal. Although the magnetic pickup is often cited as an everyday application of Faraday’s law, few sources mention the distortion that the pickup generates when converting the motion of a string to an electric signal, and fewer analyze and explain this distortion. We model the magnet and ferromagnetic wire as surfaces with magnetic charge and construct an intuitive model that accurately predicts the output of a magnetic guitar pickup. This model can be understood by undergraduate students and provides an excellent learning tool due to its straightforward mathematics and intuitive algorithm. Experiments show that it predicts the change in a magnetic field due to the presence of a ferromagnetic wire with a high degree of accuracy.

1.
Raymond A.
Serway
and
Robert J.
Beichner
,
Physics for Scientists and Engineers with Modern Physics
(
Saunders College Publishing
,
Philadelphia
,
2000
), pp.
983
984
.
2.
John D.
Cutnell
and
Kenneth W.
Johnson
,
Physics
(
Wiley
,
New York
,
1992
), p.
649
.
3.
J.
Walker
,
D.
Halliday
, and
R.
Resnick
,
Fundamentals of Physics
, 8th ed. (
Wiley
,
Hoboken, NJ
,
2008
), pp.
796
797
.
4.
Raymond A.
Serway
and
John W.
Jewett
,
Principles of Physics
, 3rd ed. (
Harcourt
,
Fort Worth, TX
,
2002
), Vol.
2
, pp.
983
984
.
5.
Neville H.
Fletcher
and
Thomas D.
Rossing
,
The Physics of Musical Instruments
(
Springer
,
New York
,
1998
), pp.
262
263
.
6.
Donald E.
Hall
,
Musical Acoustics
, 3rd ed. (
Brooks/Cole
,
Pacific Grove, CA
,
2002
), pp.
186
187
.
7.
Guy
Lemarquand
and
Valérie
Lemarquand
, “
Calculation method of permanent-magnet pickups for electric guitars
,”
IEEE Trans. Magn.
43
,
3573
3578
(
2007
).
8.
Wolfgang
Panofsky
and
Melba
Phillips
,
Classical Electricity and Magnetism
, 2nd ed. (
Addison-Wesley
,
Reading, MA
,
1962
), pp.
139
144
.
9.
Donald J.
Griffiths
,
Introduction to Electrodynamics
, 3rd ed. (
Prentice Hall
,
Upper Saddle River, NJ
,
1999
), pp.
232
233
.
10.
Thomas
Jungmann
, “
Theoretical and practical studies on the behavior of electric guitar pick-up
,” Ph.D. thesis, Department of Electrical Engineering Acoustics Laboratory,
Helsinki University of Technology
,
1994
.
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