DEE10013 PRACTICAL WORK 2

Department of Electrical Engineering

DEE10013 – MEASUREMENT DEVICES

PROGRAMME :
PRACTICAL WORK NO :2
TITLE : D'ARSONVAL METER MOVEMENT USED

DATE IN DC VOLTMETERS
LECTURER’S NAME :
: 1)

2)

PRACTICAL SKILL ATTAINMENT LAB REPORT ATTAINMENT
ASSESSMENT ASSESSMENT

(PLO5, CLS3a, CLO2) S1       RESULT 

Able to built a DC Voltmeter S2  ANALYSIS/ 
using PMMC S3  DISCUSSION 

Able to construct a series circuit S4      

Able to measure voltage drop at S5       CONCLUSION
every resistor in series circuit
S1      
Score (30)
S2      
Percentage (80%)
S3      
S4       Score (30)

S5      

S1      

S2      

S3      
S4       Percentage (20%)

S5      

S1
S2 S1

S3
S4 S2

S5 Total CA Marks S3
S1 (100%)

S2
S3 S4

S4
S5 S5

BIL GROUP MEMBERS REGISTRATION NO.
S1
S2
S3
S4
S5

PRACTICAL SKILL RUBRIC (PLO5, CLS3a)

SCORE DESCRIPTION

10 Student can COMPLETE ALL tasks assigned WITHOUT errors

8 Student can COMPLETE ALL tasks assigned WITH A FEW errors

6 Student can COMPLETE ALL tasks assigned WITH MORE errors

4 Student can COMPLETE PARTIAL tasks assigned WITHOUT error

2 Student can COMPLETE PARTIAL tasks assigned A FEW error

0 Student show no response/task not attempted.

Report Excellent Very Good Good Fair Unsatisfactory
Componet 10
(PLO1, LD1)

8 642

Analysis All point of Most point of Some point of Some point of Very few point
/Discussion discussion on the discussion on the discussion on the discussion on the of discussion on
results obtained results obtained results obtained results obtained the results
. Ability to covered and covered and elaborated covered and covered and but obtained covered
present, elaborated elaborated not properly and elaborated
interpret and elaborated
analyze
result.

Conclusion Conclusion The closing paragraph The closing The closing No Conclusion
includes wheather summarizes and draw a paragraph paragraph do not was included in
. Provide the findings sufficient conclusion attempts to attempts to the report.
answer supported the summarize but summarize the
to objective hypothesis,possible draws a weak experiment OR
stated sources of error, conclusion shows little effort
earlier. and what was and reflection
learned from the
. Ability to experiments.
learn
something
from
experiment

SESSION : 1-2021/2022 Page 2

ELECTRICAL ENGINEERING DEPARTMENT
DEE10013 MEASUREMENT DEVICES

Practical Work : 2

Topic : D'ARSONVAL METER MOVEMENT USED IN DC VOLTMETERS
[CLO1, CLO2, CLO3, C3, P4, A3, CLS1, CLS3a, CLS3b]

Learning Outcomes: At the end of experiment, the student will be able:
a) To build a DC Voltmeter using PMMC
b) To measure voltage drop at every resistor in series circuit
c) To calculate the percentage of error

Equipments : 1. DC Power Supply unit
2. Basic Electronic Circuit Trainer (BECT)

Theory :

The permanent magnet moving coil instruments are most accurate type for direct current measurements.
The action of these instruments is based on the motoring principle. When a current carrying coil is placed in
the magnetic field produced by permanent magnet, the coil experiences a force and moves. As the coil is
moving and the magnet is permanent, the instrument is called permanent magnet moving coil instrument.
This basic principle is called D’Arsonval principle. The amount of force experienced by the coil is
proportional to the current passing through the coil. The PMMC instrument is shown in Figure 1 below.

Figure 1 : PMMC Instrument

PREPARED BY: APPROVED BY:
Course Lecturer Course Coordinator /
Head of Programme

………………… ………………………………

Roselinda binti Samion Nor Juhaliza Binti Md Nordin

Date : 20/9/2021 Date : 20/9/2021
SESSION : 1-2021/2022
Page 3

The power consumption in this system is very low. It requires low current for free-scale deflection (FSD). By
controlling resistance Rs in series with the meter, D'Arsonval meter can be used for voltage measurements.
The purpose of Rs is to limit the current through the meter and extend the range to measure voltage. The
circuit is as shown in Figure 2.

Figure 2 : Circuit for DC Voltmeter

The value of the multiplier resistance required to extend the voltage range is calculated as follows:

Im = deflection current of the movement
Rm = internal resistance of the movement
Rs = multiplier series resistance
V = full-range voltage of the instrument

Sensitivity S is define as, where `

Direct current voltmeters are available up to 500 V. The multiplier resistance is built into the meter. For
higher voltage ranges, Rm is mounted separately.

SESSION : 1-2021/2022 Page 4

EXPERIMENT PROCEDURES :

A) Build a DC Voltmeter

1. Calculate the multiplier resistor (Rs) with the value of voltage is 10V, the range of current is 50µA
and internal resistor is 4 kΩ

2. Measure the variable resistor depends on the value of Rs
3. Fill in the Table 1 below
4. Connect the d’Arsonval meter with the variable resistor and power supply (circuit 1) as Figure 3

below
5. Switch on the power supply and adjust the voltage slowly until the needle of d’Arsonval is full scale.

(This d’Arsonval meter now act as DC VOLTMETER with the value of full scale is 10V)

Full Scale

VT RS

Figure 3 : D’Arsonval meter with Rs and V

Table 1 : Multiplier Resistor (Rs)

CALCULATED (Rs) MEASURED (Rs) PERCENTAGE OF ERROR

Voltage, VT = 10V
IFS = 50µs
Rm = 4 kΩ

SESSION : 1-2021/2022 Page 5

B) Measure voltage drop for every resistor

1. Calculate the voltage drop for every resistor and fill in Table 2
2. Connect the circuit as Figure 4 (circuit 2)
3. Measure the voltage drop for every resistors using DC Voltmeter as you create before
4. Find the percentage of error.

Table 2 : Voltage drop

CALCULATED (V) MEASURED (V) PERCENTAGE OF ERROR

Voltage Drop at R1

Voltage Drop at R2

SESSION : 1-2021/2022 Page 6

DISCUSSION :
1. What is the sensitivity value of meter movement (µ ammeter) that you use in Figure 3?

2. Based on circuit at Figure 4, measure voltage drop for every resistor by using DC Voltmeter, analog and
digital multimeter. Discuss your result.

VOLTAGE DC VOLTMETER ANALOG MULTIMETER DIGITAL MULTIMETER
DROP

R1

R2

Discussion

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3. Illustrate the circuit connection of DC voltmeter that you had built to measure a voltage drop at 1.5KΩ

SESSION : 1-2021/2022 Page 7

CONCLUSION:

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SESSION : 1-2021/2022 Page 8