THE TECHNICAL UNIVERSITY OF MOMBASA
SCHOOL OF ENGINEERING AND TECHNOLOGY
BACHELOR OF TECHNOLOGY IN ELECTRICAL AND ELECTRONICS
ENGINEERING
SECOND YEAR, FIRST SEMESTER.
TEE 4209 - ELECTROMAGNETIC FIELD AND WAVES.
LAB TWO: POTENTIOMETER
UNIT LECTURER: MR SANDE STEPHEN
UNIT TECHNOLOGIST: Madam BIBIYE MAHMOUD
DATE SUBMITTED:
Group 6 members :
NAME REG NUMBER SIGNATURE
1.KIBET BRYON MUTAI BTEE/350J/2021
2.KIMUTAI TIMOTHY BTEE/351J/2021
KIPKOSGEI
3.JEROME WEKESA BTEE/352J/2021
KULABUSIA
4.COLLINES YANGA BTEE/354J/2021
5.BARARE CALVIN BTEE/355J/2021
OTIENO
INTRODUCTION:
A potenti ometer is an electronic element defi ned as a three-terminal variable resistor in
which the resistance is varied manually to control the current fl ow. The most popular
type of variable resistor and potenti ometer is the linear type. Linear potenti ometers are
common in a variety of applicati ons, but it is mostly used to calculate the voltage in a
circuit.
OBJECTIVE:
The purpose of this experiment Is to determine the relation between the linear shift and
the voltage available on the cursor of the linear potentiometer.
EQUIPMENT:
• Signal conditioner module SC-7D
• Digital multimeter
• Vernier Caliper
• Actuator of unit TU-7C
• Linear Potentiometer module APC900
BACKGROUND THEORY:
Linear potentiometers are often rod actuated and connected to an internal slider or
wiper carrier. The rod will be connected to a device or object which requires
measurement. The linear potentiometer proportionally divides an applied regulated
voltage over its operational range and provides a proportional voltage output
relevant to the position of the wiper.
Linear potentiometers are a contacting type of sensor which means that the moving
2 | Page
parts make contact with each other during use. This makes them sufficiently robust
to be used within a variety of applications whilst remaining relatively inexpensive.
They can function in wide temperature ranges and offer long life, high accuracy
and repeatability.
PROCEDURE.
1. Fit module SC-7D in the console of mod. APC-900.
1. Connect the output of the linear potentiometer of unit TU-7C to the input of module SC-7D.
2. Connect the multimeter set for d.c. voltage measurements at the proportional output of
module SC-7D.
3. Connect the power supply of module SC-7D and switch it on. Check if the measure voltage
is null in the position 0; if not, calibrate the signal conditioner module SC-7D again.
4. Increase 2mm by 2mm, the position of the values set by the actuator of unit and read the
values on the multimeter (use a caliper for a correct positioning).
5. Fill a table with the measured values (figure 8.15) and plot a graph with the movements on
the x-axis and the measured voltages on the y-axis. (figure.8.17)
6. Draw a curve which better approximates the points on the graph, this is characteristic curve
of the transducer.
OBSERVATIONS
Position in mm Measured value.
0 0
2 0.147
4 0.383
6 0.553
8 0.749
10 0.970
12 1.152
14 1.349
16 1.554
18 1.739
20 1.921
22 2.159
24 2.337
26 2.532
28 2.702
30 2.899
3 | Page
ANALYSIS:
Figure 1:analysis of a linear potentiometer , measured voltage against current.
CHALLENGES
1. Fluctuating values while reading the digital multimeter.
2. A group consists of a large number of students hence not every student can participate in
doing the experiment.
4 | Page
3. A Limited number of functioning equipment in the laboratory
CONCLUSION:
The voltage available on the cursor increases with increase in linear shift. That is
from the results obtained and the graph (corresponding increase in voltage from 0
to 2.899V)
RECCOMENDATION:
1. The students should read the first value as soon as it appears.
2. The laboratory technician should check the equipment prior the experiment.
3. More equipment be availed to accommodate smaller groups.
APPLICATION:
1. Audio control. Linear potentiometers are used to control audio equipment like audio mixers
and graphic equalizers for changing the loudness and other audio related signals. This is be-
cause they are easy to visualize from the position of the slider.
2. Linear potentiometers are used in the test lab to measure displacement along a single axis
either up or down or left and right.
3. In industries linear potentiometers are used for length measurement. Linear potentiometers
are easy to install and offer precise measurement values even under difficult conditions.
REFERENCES
1. https://www.waycon.biz/products/linear-potentiometers/applications-linear-potentiometers/
#:~:text=Linear%20potentiometer%20%2D%20stroke,at%20high%20pressure – explanation
of the application of a linear potentiometers in stroke measurement.
2. https://www.variohm.com/news-media/technical-blog-archive/what-is-a-linear-potentiome-
ter-#:~:text=Mobile%20Vehicle,Motorsport%20applications –explanations of applications of
a linear potentiometer in medical applications.
3. https://www.variohm.com/news-media/technical-blog-archive/uses-of-linear-potentiome-
ters#:~:text=Boma7%20wheelchair%20from%20%C2%A0Molten%20Rock%3A%20this
%20wheelchair%20is%20designed%20to%20be%20used%20on%20all%20terrain.%20Our
%20ELPM%20linear%20potentiometers%20were%20selected%20for%20use%20in%20the
%20steering%20system%20due%20to%20its%20size%20and%20ability%20to%20en-
5 | Page
counter%20the%20harsh%20environments. –explanation of application of linear potentiome-
ter in Boma7 wheelchair from Molten Rock.
6 | Page
