1611947948665_bobinas de helmholtz

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LABORATORY 4 
Helmholtz coils 
 
Melanie Babilonia M1, Rubén Blanco B1, Daniela Domínguez M1, Alejandro Ramos G1. 
1. Chemistry program students 
__________________________________________________________________________ 
Universidad De Cartagena, Facultad Ciencias Exactas Y Naturales 
2020 
 
ABSTRACT 
In the following report he describes and put into practice the theorical study; the methods used 
in the virtual practice of Helmholtz coils, where they are shown in a simple and summared 
way. 
Through an in-depth analysis of the concepts of Helmholtz coils, electric currents, and 
magnetic field, the spacing at which a uniform magnetic field is produced is investigated and 
the superposition of the two individual fields to form the combined field of the pair of coils is 
demonstrated. % error 2% 
Key words: coils, Helmholtz, electric currents, magnetic field, spatial distribution. 
__________________________________________________________________________ 
INTRODUCTION 
It is known that magnetic fields are produced by electric currents that are associated with 
electrons in atomic orbits, and that the magnetic field is the force exerted on moving fields. In 
this way it can be affirmed that there are many ways to form a magnetic field and thus do 
various tests with it to find out what relationship with various factors to evaluate. In this case, 
Helmholtz coils will be evaluated, which are very useful for forming magnetic fields uniforms, 
and will be used to fill in the data required in the work guide. 
 
_________________________________________________________________________ 
OVERALL OBJECTIVE 
• Analyze the spatial distribution 
of the magnetic field between a 
pair of Helmholtz coils. 
 
SPECIFIC OBJECTIVES 
 
✓ Acquire practical knowledge about 
the spatial distribution of the 
 
 
intensity of the magnetic field 
generated by Helmholtz coils. 
✓ Analyze the spatial distribution of 
the magnetic field 
THEORETICAL FRAMEWORK 
• Magnetic Field 
 Magnetic fields are produced by electric 
currents, which can be macroscopic 
currents in wires, or microscopic currents 
associated with electrons in atomic orbits. 
The magnetic field B is defined as a 
function of the force exerted on moving 
charges in the Lorentz force law. The 
interaction of the magnetic field with the 
charges leads us to numerous practical 
applications. The sources of magnetic fields 
are essentially dipolar in nature, having a 
magnetic north and south pole. 
• Helmholtz coils 
 Helmholtz coils are a pair of circular coils 
on a common axis with equal currents 
flowing in the same direction. For a given 
coil radius, the spacing required to achieve 
a uniform center field can be calculated. 
This spacing is equal to the radius of the 
coils. The magnetic field lines for this 
geometry are illustrated below. 
Figure 1. magnectic field lines for helmholtz coils 
The magnetic field on the center line of a 
current loop can be calculated from the 
Biot-Savart law. The magnetic field of the 
two loops of the Helmholtz coil 
arrangement can be obtained by 
superimposing the two constituent fields. 
To find the value of this magnetic field, 
taking into account that there are two 
coils. (hyperphysics.phy) 
MATERIALS AND EQUIPMENT 
✓ HYWE TESLAMETER, DIGITAL 
✓ HELMHOLTZ COILS, ONE 
PAIR 
✓ PHYWE Universal power supply 
DC 
✓ Hall probe, axial 
✓ DIGITAL MULTIMETER 
✓ Expert conical foot 
✓ Graduated ruler, 
✓ Double nut 
✓ Universal clamp 
✓ Stainless steel rod, 18/8, 250 mm 
✓ Connection cable, 32 A, 500 mm, 
blue 
✓ Connection cable, 32 A, 500 mm, 
red 
 
 
EXPERIMENTAL DESIGN 
1. To measure the magnetic flux 
density along the z-axis of the flat 
coils when the distance between 
them alpha = R(R = radius of the 
coils) and when it is larger and 
smaller than this. 
2. To measure the spatial distribution 
of the magnetic flux density when 
the distance between coils alpha = 
R, using the rotational symmetry of 
the set-up: a) measurement of the 
axial component Bz; b) 
measurement of radial component 
Br. 
3. To measure the radial components 
B´r and B"r of the two individual 
coils in the plane midway between 
them and to demonstrate the 
overlapping of the two fields at Br = 
0 
 DATA ANALYSIS 
I (A) B (mT) 
4.12 2.2 
4.12 2.11 
4.12 2.09 
3.88 2 
3.76 1.91 
3.68 1.86 
3.44 1.77 
3.27 1.7 
3.24 1.65 
3.15 1.61 
3.08 1.51 
2.97 1.5 
2.87 1.44 
2.84 1.4 
2.76 1.37 
2.55 1.27 
 
N = 124 number of turns of the coil. 
R = 14.5 cm coil radius. = 0.145m 
M = 0.5542×10-3 (slope) 
𝜇0 = 1.26×10-6 
B = 
𝜇0𝐼𝑁
2𝑅
 
M = 
𝜇0𝑁
2𝑅
 
N = 
𝑀×2𝑅
𝜇0
 
N = 
0,5542×10−3(2×0.145)
1.26×10−6
 
N = 127 
% Error = 
|𝑎𝑝𝑝𝑟𝑜𝑥−𝑒𝑥𝑎𝑐𝑡|
𝑒𝑥𝑎𝑐𝑡
× 100 
% Error = 
127−124
124
× 100 
 % Error = 2% 
 
 
 
 
HELMHOLTZN COIL 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
y = 0.5542x - 0.1533
R² = 0.9899
0
0.5
1
1.5
2
2.5
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
B
(m
T)
 M
ag
n
et
ic
 f
ie
ld
I (A) stream
B (mT) Linear (B (mT)) Linear (B (mT))
 
 
DISCUSSION OF RESULTS 
In calculating the number of turns that the 
helmholtz coil gives us as a result 127 laps 
and comparing it with the theoretical value 
of 124 turns, we found you have a bug 
percentage of 2% 
 
CONCLUSION 
There is a relationship between slope of the 
graph as a function of current and field, with 
a formula that exists to find it, then it can be 
said that there is a relationship between 
that slope and the value of the radius with 
the number of turns of the 
coils.(studocu.com) 
 
REFERENCES 
1. Laboratory guide by javier 
Trujillo, year 2020. 
2. http://hyperphysics.phy-
astr.gsu.edu/hbasees/magne 
c/mag!e.html 
3. Studocu. Physics 
electromagnetic