laboratory workbook (electrical technology)
DESCRIPTION
For student polytechnic who register Course DJJ2022 (ELECTRICAL TECHNOLOGY)TRANSCRIPT
DJJ 2022 – ELECTRICALTECHNOLOGY
[Document subtitle]
[DATE]GRIZLI777
[Company address]
i
TABLE OF CONTENTPAGE
TABLE OF CONTENT ................................................................................................................................. i
1 EXPERIMENT 1 : UNIT CONVERSION AND MEASUREMENT............................................................1
1.1 AIM..........................................................................................................................................1
1.2 OUTCOMES .............................................................................................................................1
1.3 EQUIPMENTS/MATERIALS NEEDED ........................................................................................1
1.4 THEORY ...................................................................................................................................1
1.5 ELECTRIC AND MAGNETIC QUANTITIES..................................................................................2
1.6 INTRODUCTION TO ANALOGUE MULTIMETER .......................................................................3
1.7 LABEL OF EACH INDICATOR ON THE ANALOGUE MULTI METER............................................3
1.7.1 Resistance Measurement................................................................................................4
1.7.2 DC Voltage Measurement...............................................................................................5
1.7.3 DC Current Measurement...............................................................................................5
Taking accurate readings .......................................................................................................................6
Precautions .............................................................................................................................................6
Multi meters are easily damaged by careless use so please take these steps: ...................................6
1.7.4 EXAMPLE MEASUREMENT METHOD OF ANALOGUE MULTI METER..............................6
1.7.4.1 DC Voltage Measurement ( unit volt) .........................................................................6
1.7.4.2 Resistor value measurement (unit Ω) .........................................................................7
1.7.4.3 DC Ampere measurement (unit mA) ..........................................................................7
1.7.4.4 AC volt measurement (unit volt).................................................................................8
1.8 INTRODUCTION TO RESISTOR.................................................................................................9
1.9 INTRODUCTION TO BREAD BOARD.......................................................................................11
1.9.1 How it work...................................................................................................................11
1.9.1.1 Series Connection .....................................................................................................12
1.9.1.2 Parellel Connection ...................................................................................................13
ii
1.10 CALCULATION........................................................................................................................14
1.11 EXPERIMENTAL PROCEDURES............................................................................................1-15
1.12 QUESTIONS ...........................................................................................................................16
1.13 DISCUSSIONS.........................................................................................................................17
1.14 CONCLUSION.........................................................................................................................19
1.15 REFERENCES ..........................................................................................................................19
2 EXPERIMENT 2: ELECTRICAL CIRCUITS: SERIES AND PARALLEL CIRCUITS.....................................20
2.1 AIM........................................................................................................................................20
2.2 OUTCOMES ...........................................................................................................................20
2.3 EQUIPMENTS/MATERIALS NEEDED ......................................................................................20
2.4 THEORY .................................................................................................................................21
2.4.1 INTRODUCTION TO SERIES, PARALLEL AND SERIES PARALLEL CIRCUIT........................21
2.4.1.1 Series Circuit..............................................................................................................21
2.4.1.2 Parallel Circuit ...........................................................................................................22
2.5 EXPERIMENTAL 2A: SERIES PROCEDURES.............................................................................23
2.5.1 DATA AND RESULT 2A : .................................................................................................26
2.6 EXPERIMENTAL 2B: PARALELL PROCEDURES........................................................................28
2.6.1 DATA AND RESULT EXPERIMENT 2B: ............................................................................32
2.6.2 Draw THE PARALLEL circuit connection ON THE PROTOBOARD:.................................33
2.7 DISCUSSIONS.........................................................................................................................34
2.8 CONCLUSION.........................................................................................................................37
2.9 REFERENCES ..........................................................................................................................37
3 EXPERIMENT 3 : TRANSFORMER...................................................................................................38
3.1 AIM........................................................................................................................................38
3.2 OUTCOMES ...........................................................................................................................38
3.3 EQUIPMENTS/MATERIALS NEEDED ......................................................................................38
3.4 THEORY .................................................................................................................................38
iii
3.4.1 Energy losses in a transformer......................................................................................40
3.5 PROCEDURE ..........................................................................................................................41
3.6 QUESTION/DISSCUSSIONS ....................................................................................................42
3.7 CONCLUSIONS.......................................................................................................................44
3.8 REFERENCES ..........................................................................................................................44
4 EXPERIMENT 4: BASIC MOTOR DC................................................................................................45
4.1 AIM........................................................................................................................................45
4.2 OUTCOMES ...........................................................................................................................45
4.3 EQUIPMENTS/MATERIALS NEEDED ......................................................................................45
4.4 THEORY .................................................................................................................................45
4.5 EXPERIMENTAL PROCEDURES...............................................................................................47
4.6 DISCUSSIONS.........................................................................................................................49
4.7 CONCLUSION.........................................................................................................................50
4.8 REFERENCES ..........................................................................................................................50
DJJ2022 – ELECTRICAL TECHNOLOGY (LABORATORY RUBRIC) .............................................................51
DJJ2022 – ELECTRICAL TECHNOLOGY (GENERIC SKILLS RUBRIC)..........................................................53
ELECTRICAL TECHNOLOGY LABORATORY 1
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1 EXPERIMENT 1 : UNIT CONVERSION AND MEASUREMENT
1.1 AIM
1. To understand how to use unit conversion
2. To introduce analogue multimeter
3. To learn using the correct meter scale
1.2 OUTCOMES
1. At the end of the session the students will able to :
2. Determine the unit conversion
3. Apply in generic skill for analogue multimeter
4. Determine the correct meter scale
1.3 EQUIPMENTS/MATERIALS NEEDED
1. Analogue Multimeter
2. Resistor
3. Breadboard
1.4 THEORY
UNIT CONVERSION
Table 1 :Decimal Multiples Table
I. DECIMAL MULTIPLES AND SUB-MULTIPLES
Name Symbol Equivalent Name Symbol Equivalenttera T 1012 deci d 10-1
giga G 109 centi c 10-2
mega M 106 milli m 10-3
kilo k 103 micro μ 10-6
hecto h 102 nano n 10-9
deca − 10 pico p 10-12
ELECTRICAL TECHNOLOGY LABORATORY 2
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1.5 ELECTRIC AND MAGNETIC QUANTITIES
Table 2 Electrical Quantities Table
Practice Exercise:
1. Complete the unit equation for each of the following resistance quantity:a. 1KΩ = …… Ω
b. 10KΩ = …… Ω
2. Complete the unit equation for each of the following capacitance quantity:equivalents:a. 1000µF = ……… F = ………mF
b. 0.07F = ……..F = ……..mF
3. Complete the unit equation for each of the following inductance quantity :a. 100mF = ……… H = ………µF
b. 0.01H = ……..mH = ……..µF
ELECTRICAL TECHNOLOGY LABORATORY 3
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1.6 INTRODUCTION TO ANALOGUE MULTIMETER
By operating a multi-position switch on the meter they can be quickly and easily set to be avoltmeter, an ammeter or an ohmmeter. In other words, this instrument is used to measureresistance, current and voltage in electric circuit. It is also used to test electronic component such asresistor, capacitor, inductor, diode, transistor and etc. Besides, we can check the condition of thesecomponents whether good or not. If we looked at the analogue multi meter, this equipment isclassified into 4 basic divisions:
A. Control UnitControl unit can be set followed by measurement unit as we need. For example, if wewant to measure alternating voltage and current (AU/AC), we must set the control unitto AVC (alternating current voltage) and so on.
B. Reading Scale
Reading scale has several curve line with certain unit such as DCV.A, AVC, and so on. Electric quantity is measured in this meter by the reading scale.
C. PointerThe pointer is moving on the reading scale to show you the value of the electric quantitybeing measured.
D. Terminal MeterThere are two terminal meter named positive terminal and negative terminal. Both ofterminal are joint to test lead where as the red colour for positive terminal (+) and blackcolour for negative terminal (-).
1.7 LABEL OF EACH INDICATOR ON THE ANALOGUE MULTI METER
Figure 1.1
POINTER READING
OFF MULTI METER
SELECTOR
DCV SELECTOR
RESISTOR SCALE
READING
DCV SCALE
READING
POINTERADJUSTMENT AT0 Volt
RESISTOR SCALE
ADJUSTMENT TO
0Ω
ACV SELECTOR
TRANSISTORTESTING
RESISTORSELECTOR
NEGATIVE
TERMINAL (-VE)
CONNECTOR
POSITIVETERMINAL (+VE)CONNECTOR
DC mA SELECTORBUZZER
ELECTRICAL TECHNOLOGY LABORATORY 4
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
Analogue meters take a little power from the circuit under test to operate their pointer. They musthave a high sensitivity of at least 20k /V or they may upset the circuit under test and give anincorrect reading.
Batteries inside the meter provide power for the resistance ranges, they will last several years butyou should avoid leaving the meter set to a resistance range in case the leads touch accidentally andrun the battery flat.
Typical ranges for analogue multi meters like the one illustrated in Figure: 1.1(the voltage and current values given are the maximum reading on each range)
DC Voltage: 0.5V, 2.5V, 10V, 50V, 250V, 1000V. AC Voltage: 10V, 50V, 250V, 1000V. DC Current: 50µA, 2.5mA, 25mA, 250mA.
A high current range is often missing from this type of meter. AC Current: None. (You are unlikely to need to measure this). Resistance: 20 , 200 , 2k , 20k , 200k .
These resistance values are in the middle of the scale for each range.
If we looked at the reading scale of multi meter, we will see many colourful curve lines. Every line is
used for certain unit such as resistance (), direct voltage and current (DCV.A), alternating voltagecurrent (ACV) and so on (see Figure 1.2).
1.7.1 Resistance Measurement
The resistance scale on an analogue meter is normally at the top, it is an unusual scale becauseit reads backwards and is not linear (evenly spaced). This is unfortunate, but it is due to theway the meter works.
1. Set the meter to a suitable resistance range.Choose a range so that the resistance you expect will be near the middle of the scale. Forexample: with the scale shown below and an expected resistance of about 50k choosethe × 1k range.
2. Hold the meter probes together and adjust the control on the front of the meter which isusually labelled "0 ADJ" until the pointer reads zero (on the RIGHT remember!).If you can't adjust it to read zero, the battery inside the meter needs replacing.
3. Put the probes across the component.Avoid touching more than one contact at a time or your resistance will upset the reading!
Figure
ELECTRICAL TECHNOLOGY LABORATORY 5
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
Choose scale range at x1. When the pointer shows at 20 scale reading, therefore the
total of resistance is 20 x 1 = 20.
1.7.2 DC Voltage Measurement
There are 3 ranges in this scale reading: 0 to 10, 0 to 50 and 0 to 250.When you want to measure a voltage not more than 50V, the suitable scaleRange is 0 to 50V. For example, if the pointer shows at 20, the total ofVoltage measured is 20V.If the voltage is around 0.1V, so suitable scale reading is 0 to 10V (10/100=0.1V). For example,if the pointer shows at 4.4, the total of voltage measured is 4.4/100=0.044V.
1.7.3 DC Current Measurement
Scale range has been choosing is 25mA. The suitable scale reading is 0 to250 (250/10=25mA). If pointer at 150, the total of current measured is 150/10=15mA.
ELECTRICAL TECHNOLOGY LABORATORY 6
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
Taking accurate readings
Precautions
Multi meters are easily damaged by careless use so please take these steps:
Always disconnect the multi meter before adjusting the range switch. Always check the setting of the range switch before you connect to a circuit. Never leave a multi meter set to a current range (except when actually taking a reading).
The greatest risk of damage is on the current ranges because the meter has a low resistance.
1.7.4 EXAMPLE MEASUREMENT METHOD OF ANALOGUE MULTI METER
1.7.4.1 DC Voltage Measurement ( unit volt)
Answer : 100 Volt
Correct
reflection hidden
Wrong
reflection visible
To take an accurate reading from an analogue scale you must
have your eye in line with the pointer.
Avoid looking at an angle from the left or right because you
will see a reading which is a little too high or too low. Many
analogue meters have a small strip of mirror along the scale
to help you. When your eye is in the correct position the
reflection of the pointer is hidden behind the pointer itself. If
you can see the reflection you are looking at an angle.
Figure: 1.3
Point
1
Point
2
ELECTRICAL TECHNOLOGY LABORATORY 7
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1.7.4.2 Resistor value measurement (unit Ω)
Answer : 1KΩ
1.7.4.3 DC Ampere measurement (unit mA)
Answer : 150 mA
Point
1
Point
1
Point
2
ELECTRICAL TECHNOLOGY LABORATORY 8
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1.7.4.4 AC volt measurement (unit volt)
Answer : 41 V
Point
2
Point
1
ELECTRICAL TECHNOLOGY LABORATORY 9
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1.8 INTRODUCTION TO RESISTOR
Resistor values can be determined using the Resistor Colour Code. For the 4-band type, the first twobands are numerical values the third is the multiplier or number of noughts. The fourth bandindicates tolerance. Resistor values are also available as 5-band types.
Example: 1st stripe: Brown = 1
2nd stripe: Black = 0
3rd stripe: Orange = x1,000
4th stripe: silver = 10% tolerance
Resistor value = 10 x 1000 = 10,000 Ω = 10kΩ
Tolerance = 10% x 10,000 = 1000
Minimum Value = Resistor Value – Tolerance = 10,000 – 1000 = 9,000Ω
Maximum Value = Resistor Value + Tolerance = 10,000 +1000 = 11,000Ω
Table 1 – Resistor Colour Code
ELECTRICAL TECHNOLOGY LABORATORY 10
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
ELECTRICAL TECHNOLOGY LABORATORY 11
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1.9 INTRODUCTION TO BREAD BOARD
A breadboard also known as protoboard is a type of solder less electronic circuit building.You canbuild an electronic circuit on a breadboard without any soldering! Best of all it is reusable. It wasdesigned by Ronald J Portugal of EI Instruments Inc. in 1971.
1.9.1 How it work
Basically, a bread board is an array of conductive metal clips encased in a box made of white ABSplastic, where each clip is insulated with another clips. There are a number of holes on the plasticbox, arranged in a particular fashion. A typical bread board layout consists of two types of regionalso called strips. Bus strips and socket strips. Bus strips are usually used to provide power supply tothe circuit. It consists of two columns, one for power voltage and other for ground.
Socket strips are used to hold most of the components in a circuit. Generally it consists of twosections each with 5 rows and 64 columns. Every column is electrically connected from inside.
ELECTRICAL TECHNOLOGY LABORATORY 12
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1.9.1.1 Series Connection
ELECTRICAL TECHNOLOGY LABORATORY 13
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1.9.1.2 Parellel Connection
ELECTRICAL TECHNOLOGY LABORATORY 14
1.10 CALCULATION
ResistorFirst Band
(Colour&digit)
Second Band
(Colour&digit)
Third Band
(multiplier)
(Colour&digit)
Resistor
ValueTolerance Min Value Max Value
1.Brown Black Red
2.Yellow Violet Brown
3.Brown Black Orange
4.Brown Green Brown
5.Orange White Red
Table 3 – Calculation result
(20 marks)
Lecturer signature: ___________________________________ Date : ____________________
ELECTRICAL TECHNOLOGY LABORATORY1-15
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1.11 EXPERIMENTAL PROCEDURES
1. By using Bread Board and resistor, connect a multimeter a shownbelow.
2. Choose ohm scale at the maximum range then reduce the rangeuntil you get the
correct answer.
3. Write the answer in Table 4, experiments result.
4. Repeat the procedure 1 until 3 to complete the Table 4.
Point
ELECTRICAL TECHNOLOGY LABORATORY 16
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
Resistor Calculation Value Experiment Value
R1
R2
R3
R4
R5
Table 4 – Experiments result
(5 marks)
1.12 QUESTIONS
1. Complete the unit equation for each of the following resistance quantity:a. 100Ω = ……..K Ω
b. 1500 Ω = ……. K Ω
(2 marks)
2. Complete the unit equation for each of the following capacitance quantity:equivalents:
a. 600µF = ……..F = ……..mF
b. 150mF = ……..F = ……..µF
(2 marks)
3. Complete the unit equation for each of the following inductance quantity :a. 6.5mH = ……..H = ……..µF
b. 750µF = ……..H = ……..Mf
(2 marks)
ELECTRICAL TECHNOLOGY LABORATORY 17
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
1.13 DISCUSSIONS
a) How to change the unit conversion.
(2marks)
b) How to choose the correct meter scale.
(6marks)
ELECTRICAL TECHNOLOGY LABORATORY 18
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
ELECTRICAL TECHNOLOGY LABORATORY 19
DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement
c) How to know the value of resistor using calculation.
(3 marks)
1.14 CONCLUSION
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
(6marks)
1.15 REFERENCES
Book:
_______________________________________________________________________
_______________________________________________________________________
Internet Address:
_______________________________________________________________________
_______________________________________________________________________
(2 marks)
50Total :
ELECTRICAL TECHNOLOGY LABORATORY 20
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
2 EXPERIMENT 2: ELECTRICAL CIRCUITS: SERIES AND PARALLEL
CIRCUITS
2.1 AIM
1. To learn using the correct meter scale
2. To analyse the series and parallel connection using breadboard
3. To study the measurement method of voltage and current in series and parallel circuit
connection
2.2 OUTCOMES
At the end of the session the students will able to:
1. Determine the correct meter scale
2. Explain the operation of the circuit
3. Explain the measurement method of voltage and current in series and parallel circuit
2.3 EQUIPMENTS/MATERIALS NEEDED
1. Analogue Multimeter
2. Resistor (150Ω, 120Ω, 160Ω)
3. Breadboard
4. 9V Battery
5. Jumper Wire
ELECTRICAL TECHNOLOGY LABORATORY 21
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
2.4 THEORY
2.4.1 INTRODUCTION TO SERIES, PARALLEL AND SERIES PARALLELCIRCUIT
2.4.1.1 Series Circuit
In a practical circuit consisting of just three resistors, connected in series across a battery, four circuit
parameters can be measured using a simple multi-meter. Firstly the current I flowing which is
determined by inserting an ammeter in series with the resistors and then the three voltage drops
across the individual resistors.
The current is a result of the applied voltage divided by the total series circuit resistance. Apply the
formula for series resistance to determine the total resistance R.
321 RRRR T
321 VVVV T
321 IIII T 33
22
11
RIV
RIV
RIV
T
T
T
Formula :
ELECTRICAL TECHNOLOGY LABORATORY 22
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
Individual resistor voltage drops are each found by applying Ohm's Law. Resistance R1, R2 or R3
multiplied by the series circuit current. Adding the individual voltage drops together will always
equal the applied battery voltage.
Series circuits are commonly used in on-board computer sensor
and actuator circuits. A series circuit has several unique
characteristics:
There is only one path for electric current. The amount of electric current is the same at all points inthe circuit. The source voltage will be dropped across all of theelectrical loads in the circuit. An open anywhere in a series circuit will stop the currentand shut off the circuit. The total circuit resistance is the sum (add them together) ofall the resistive loads in the circuit.
2.4.1.2 Parallel Circuit
The first principle to understand about
parallel circuits is that the voltage is equal
across all components in the circuit. This is
because there are only two sets of
electrically common points in a parallel
circuit, and voltage measured between sets of
common points must always be the same at any
given time. Therefore, in the above circuit, the
voltage across R1 is equal to the voltage across
R2 which is equal to the voltage across R3 which
is equal to the voltage across the battery.
321 VVVV T
321 IIII T 3
3
2
2
1
1
R
VI
R
VI
R
VI
T
T
T
ELECTRICAL TECHNOLOGY LABORATORY 23
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
2.5 EXPERIMENTAL 2A: SERIES PROCEDURES
1. Calculate the total resistance, current and voltage for each resistance in series circuit as
shown in figure 1 using the related formula. Measure the battery given.
Fig. 1: series circuit
2. Construct the three resistors in series on the protoboard as shown in figure 2 below.
Fig. 2: construction of series circuit on protoboard
Given equipment:
1. Battery =_________v
2. R1 = 150 Ω
3. R2 =120 Ω
4. R3 = 160 Ω
ELECTRICAL TECHNOLOGY LABORATORY 24
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
3. Using the multimeter, measure and record the current and voltage across R1, R2 and R3.
Current measurement:
Fig. 3: Measuring Itotal or I1 in series circuit
Fig. 4: Measuring I2 in series circuit
Fig. 5: Measuring I3 in series circuit
Disconnect the given series circuit at point between the batteryand R1.
Connect the multimeter at that point as shown in fig.3.
Make sure that the multimeter is in current measurementmode.
The measured current value of Itotal =____________
Itotal = I1
So, I1 = ______________
Reconstruct the circuit as shown in fig. 1.
Disconnect the given series circuit at point between the R1 andR2.
Connect the multimeter at that point as shown in fig. 4.
Make sure that the multimeter is in current measurementmode.
The measured current value of I2 =____________
Reconstruct the circuit as shown in fig. 1.
Disconnect the given series circuit at point between the R2 andR3.
Connect the multimeter at that point as shown in fig. 5.
Make sure that the multimeter is in current measurementmode.
The measured current value of I3 =____________
ELECTRICAL TECHNOLOGY LABORATORY 25
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
Voltage measurement
Fig. 6: Measuring Vtotal in series circuit
Fig. 7: Measuring V1 in series circuit
Fig. 8: Measuring V2 in series circuit
Reconstruct the circuit as shown in fig. 1.
Connect the multimeter at that point as shown in fig. 6.
Make sure that the multimeter is in voltage measurementmode.
The measured voltage value of Vtotal =____________
Disconnect the multimeter from the circuit.
Connect the multimeter at that point as shown in fig. 7.
Make sure that the multimeter is in voltage measurementmode.
The measured voltage value of V1 =____________
Disconnect the multimeter from the circuit.
Connect the multimeter at that point as shown in fig. 8.
Make sure that the multimeter is in voltage measurementmode.
The measured voltage value of V2 =____________
ELECTRICAL TECHNOLOGY LABORATORY 26
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
Fig. 9: Measuring V3 in series circuit
2.5.1 DATA AND RESULT 2A :
Experimental Data:
Electric QuantitiesValue indicated by multimeter
Resistor 1 (R1) Resistor 2 (R2) Resistor 3 (R3) Total
Voltage
V1 V2 V3 VT
Current
I1 I 2 I 3 I T
Table 1 – Measurement value for series circuit
(8 marks)
Lecturer’s signature : ____________________________ Date : _________________
Disconnect the multimeter from the circuit.
Connect the multimeter at that point as shown in fig. 9.
Make sure that the multimeter is in voltage measurementmode.
The measured voltage value of V3 =____________
ELECTRICAL TECHNOLOGY LABORATORY 27
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
DRAW THE SERIES CIRCUIT CONNECTION ON THE PROTOBOARD:
(5 marks)
Lecturer’s signature: ____________________________ Date: _________________
ELECTRICAL TECHNOLOGY LABORATORY 28
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
2.6 EXPERIMENTAL 2B: PARALELL PROCEDURES
1. Calculate the total resistance, current and voltage for each resistance in parallel circuit
as shown in figure 1 using the related formula. Measure the battery given.
Current measurement
Fig. 10: Parallel circuit
2. Construct the three resistors in series on the protoboard as shown in figure 2 below.
Fig. 11: construction of parallel circuit on protoboard
3. Using the multimeter, measure and record the current and voltage across R1, R2 and R3.
Connect the given parallel circuit on a protoboard.
Given equipment:
1. Battery =_________v2. R1 = 150 Ω3. R2 = 120 Ω4. R3 = 160 Ω
ELECTRICAL TECHNOLOGY LABORATORY 29
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
Current measurement:
Fig. 12: Measuring Itotal in parallel circuit
Fig. 13: Measuring I1 in parallel circuit
Fig. 14: Measuring I2 in parallel circuit
Disconnect the given parallel circuit at point between thebattery and junction of R1, R2 and R3.
Connect the multimeter at that point as shown in fig. 12.
Make sure that the multimeter is in current measurementmode.
The measured current value of Itotal =____________
Reconstruct the circuit as shown in fig. 10.
Disconnect the given parallel circuit at point between thejunction of R1 with junction of R2 and R3.
Connect the multimeter at that point as shown in fig. 13.
Make sure that the multimeter is in current measurementmode.
The measured current value of I1 =____________
Reconstruct the circuit as shown in fig. 10.
Disconnect the given parallel circuit at point between thejunction of R2 with junction of R1 and R3.
Connect the multimeter at that point as shown in fig. 14.
Make sure that the multimeter is in current measurementmode.
The measured current value of I2 =____________
ELECTRICAL TECHNOLOGY LABORATORY 30
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Fig. 15: Measuring I3 in parallel circuit
Voltage measurement
Fig. 16: Measuring Vtotal in parallel circuit
Fig. 17: Measuring V1 in parallel circuit
Reconstruct the circuit as shown in fig. 10.
Disconnect the given parallel circuit at point between thejunction of R3 with junction of R1 and R2.
Connect the multimeter at that point as shown in fig. 15.
Make sure that the multimeter is in current measurementmode.
The measured current value of I3 =____________
Reconstruct the circuit as shown in fig. 10.
Connect the multimeter at that point as shown in fig. 16.
Make sure that the multimeter is in voltage measurementmode.
The measured voltage value of Vtotal =____________
Disconnect the multimeter from the circuit.
Connect the multimeter at that point as shown in fig. 17.
Make sure that the multimeter is in voltage measurementmode.
The measured voltage value of V1 =____________
ELECTRICAL TECHNOLOGY LABORATORY 31
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Fig. 18: Measuring V2 in parallel circuit
Fig. 19: Measuring V3 in parallel circuit
Disconnect the multimeter from the circuit.
Connect the multimeter at that point as shown in fig. 18.
Make sure that the multimeter is in voltage measurementmode.
The measured voltage value of V2 =____________
Disconnect the multimeter from the circuit.
Connect the multimeter at that point as shown in fig. 19.
Make sure that the multimeter is in voltage measurementmode.
The measured voltage value of V2 =____________
ELECTRICAL TECHNOLOGY LABORATORY 32
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2.6.1 DATA AND RESULT EXPERIMENT 2B:
Experimental Data:
Electric QuantitiesValue indicated by multimeter
Resistor 1 (R1) Resistor 2 (R2) Resistor 3 (R3) Total
VoltageV1 V2 V3 VT
Current
I1 I 2 I 3 I T
Table 3 – Measurement value for parallel circuit
(8 marks)
Lecturer’s signature : ____________________________ Date : _________________
ELECTRICAL TECHNOLOGY LABORATORY 33
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
2.6.2 Draw THE PARALLEL circuit connection ON THE PROTOBOARD:
(5 marks)
Lecturer’s signature: ____________________________ Date: _________________
ELECTRICAL TECHNOLOGY LABORATORY 34
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
2.7 DISCUSSIONS
1. By referring the series circuit as shows, complete the table below with a calculation:
Fig. 1: series circuit
Electric QuantitiesValue calculated
Resistor 1 (R1) Resistor 2 (R2) Resistor 3 (R3) Total
Voltage V1 V2 V3 VT
Current I1 I 2 I 3 I T
Table 2 –Calculated value for series circuit
(12 marks)
ELECTRICAL TECHNOLOGY LABORATORY 35
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
2. By referring the series circuit as shows, Complete the table below with a calculation :
Fig. 10: Parallel circuit
Electric QuantitiesValue calculated
Resistor 1 (R1) Resistor 2 (R2) Resistor 3 (R3) Total
Voltage V1 V2 V3 VT
Current I1 I 2 I 3 I T
Table 4 –Calculated value for series circuit
(12 marks)
ELECTRICAL TECHNOLOGY LABORATORY 36
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
3. State the Ohm’s Law
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(6 marks)
4. State the use of resistors.
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(2 marks)
5. What is the effect of a resistor in a circuit?
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(2 marks)
6. What is the connection between the resistors size and value of current flow?
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(2 marks)
ELECTRICAL TECHNOLOGY LABORATORY 37
DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits
2.8 CONCLUSION
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(6marks)
2.9 REFERENCES
Book :
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Internet Address :
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(2 marks)
70Total :
ELECTRICAL TECHNOLOGY LABORATORY 38
DJJ 2022 – ELECTRICAL TECHNOLOGY Transformer
3 EXPERIMENT 3 : TRANSFORMER
3.1 AIM
1. To determine the output voltage of step down transformer
2. To determine the transformer turns ratio
3.2 OUTCOMES
At the end of the session the students will able to :
1. Explain the operation of transformer
2. Apply in generic skill for analogue multimeter
3. Explain the transformer turns ratio
3.3 EQUIPMENTS/MATERIALS NEEDED
1. Analogue Multimeter
2. Transformer
3. Power Supply
3.4 THEORY
A transformer is a device used to change voltages and currents of AC electric power. In thesimplest version it consists of two windings wrapped around a magnetic core; windings arenot electrically connected, but they are coupled by the magnetic field, as it shown in Figure 1.When one winding is connected to the AC electric power, the electric current is generated.
This winding is called the primary winding. The primary current produces the magnetic fieldand the magnetic flux links the second winding, called the secondary winding. The AC fluxthrough the secondary winding produces an AC voltage, so that if some impedance isconnected to the terminals, an AC electric current is supplied. Figure 2 shows the schematicsymbols of a transformer.
ELECTRICAL TECHNOLOGY LABORATORY 39
DJJ 2022 – ELECTRICAL TECHNOLOGY Transformer
Figure 1: Sketch of an ideal transformer.
Figure 2: Schematic symbols of a transformer.
The simplest model of the transformer is called the ideal transformer and it neglectsany power losses and leakage magnetic fluxes. Assuming that the primary winding has Npturns of wire, and the secondary winding has Ns turns, the relationship between the primaryvoltage and the secondary voltage is
Where a is the turns ratio in the primary and secondary windings
ELECTRICAL TECHNOLOGY LABORATORY 40
DJJ 2022 – ELECTRICAL TECHNOLOGY Transformer
Similarly, for the primary and secondary currents
For AC power the same can be also expressed in the phasor notation
If the secondary voltage is less than the primary voltage, the transformer is known as a STEP-DOWN transformer. If the secondary voltage is greater than the primary voltage it is knownas a STEP-UP transformer
A voltage change from primary to secondary will mean a current change also. If the voltageis increased the current will be decreased and vice versa. So a 20:1 step-down transformerfor voltage will be a 20:1 step-up transformer for current.
Bigger currents need thicker wire and so step down transformers have primary coils of thinwire and secondary coils of thick wire.
Examples of step up and step down transformers:(a) Step down: electric mains clock, stereo, substation, low voltage power supplies, andaudio systems in televisions.(b) Step up: power station end of transmission cables, electron gun in a TV, "starter" coils influorescent lights.
3.4.1 Energy losses in a transformer
These formulae are only correct if the transformer is 100% efficient but of course they neverare. Energy is always lost and so the output voltage will be a little smaller than the calculatedvalue.
Energy can be lost as:(a) heat in the coils because of the resistance of the wire;(b) incomplete transfer of magnetic field;(c) heating of the core due to induced currents in it. This is reduced by making the core outof insulated soft iron in laminated strips. If this were not done the cores of largetransformers would get so hot that they would melt.
ELECTRICAL TECHNOLOGY LABORATORY 41
DJJ 2022 – ELECTRICAL TECHNOLOGY Transformer
3.5 PROCEDURE
1. Make a connection as shown in Figure 3.
2. Set the range selector to 250ACV or higher.
3. Connect the probe of the multimeter to the secondary side of the transformer.
4. Do not turn the power on before your circuit has been checked by your lecturer.
5. When the layout has been completed, have your lecturer to check your circuit connections.
6. Adjust the ACV range selector to gain a proper reading.
7. Show the measured value.
Figure 3: Experimental transformer measurement
Measured output voltage at the secondary windings=_______________V
Measured output voltage at the secondary windings=_______________V
ELECTRICAL TECHNOLOGY LABORATORY 42
DJJ 2022 – ELECTRICAL TECHNOLOGY Transformer
3.6 QUESTION/DISSCUSSIONS
1. What is the windings ratio of the transformer?
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(4 marks)
2. Complete the following table as an example 1. Show all the calculation.
(6 marks)
eNoo Primaryvoltage
Secondaryvoltage
Primaryturns
Secondaryturns
Primarycurrent
secondarycurrent
1 12V 240V 100 2000 1A 0.05A
2 240V 12V 5000 0.1A
3 100V 2000 100 2A
4 200V 200 10000 1A
ELECTRICAL TECHNOLOGY LABORATORY 43
DJJ 2022 – ELECTRICAL TECHNOLOGY Transformer
1. Draw the input and output waveform of the transformer.
Input voltage
(5 marks)
Output voltage
(5 marks)
ELECTRICAL TECHNOLOGY LABORATORY 44
DJJ 2022 – ELECTRICAL TECHNOLOGY Transformer
3.7 CONCLUSIONS
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(5 marks)
3.8 REFERENCES
Book :
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Internet Address :
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(5 marks)
(2 marks)
30Total :
ELECTRICAL TECHNOLOGY LABORATORY 45
DJJ 2022 – ELECTRICAL TECHNOLOGYBasic DC Motor
4 EXPERIMENT 4: BASIC MOTOR DC
4.1 AIM
3. To design basic motor DC
4.2 OUTCOMES
At the end of the session the students will able to :
1. To determine the direction of the magnetic field.
2. To determine the speed at which the motor turns by;
a. Increasing the number of current carrying wires (number of loops in the rotor)
b. Increasing the size of the magnetic field by using additional and/or stronger
ceramic magnets
4.3 EQUIPMENTS/MATERIALS NEEDED
1. Copper Wire
2. Paper Clips
3. Wood (3" 1X2)
4. Neodymium Magnet
5. Battery (AA)
6. Insulated Wire
7. Sand Paper
4.4 THEORY
Motors convert electrical energy (from a battery or voltage source) into mechanical energy
(used to cause rotation). When a wire that carries current is placed in a region of space that
has a
magnetic field, the wire experiences a force.
The size of the force, which determines how fast the motor spins, depends on :
a. the amount of current in the wire
b. the length of the wire
c. the strength of the magnetic field
ELECTRICAL TECHNOLOGY LABORATORY 46
DJJ 2022 – ELECTRICAL TECHNOLOGYBasic DC Motor
The direction of the force, which determines which direction the motor spins, depends on:
a. the direction of the current in the wire
b. the direction of the magnetic field
The Right Hand Rule is used to determine the direction of the force when the direction of
the current and the direction of the magnetic field are known.
Thumb = direction of current
Fingers = dir. of magnetic field
Palm = direction of force
ELECTRICAL TECHNOLOGY LABORATORY 47
DJJ 2022 – ELECTRICAL TECHNOLOGYBasic DC Motor
4.5 EXPERIMENTAL PROCEDURES
1. Cut a length of copper wire (between 2 and 3ft) using a pair of wire cutters.
2. Use a AA Battery as a winding template; begin winding the Copper Wire around the
AA Battery (Make sure to leave about two inches of wire trailing off one end of the
coil).
3. Continue winding the Copper Wire around the AA Battery; make sure that you wind
a nice tight coil.
4. Leave a length of wire (two inches) trailing from your coil after winding the Copper
Wire around the AA Battery 15 times.
5. Wrap the trailing ends of wire around your coil two or three times. This will hold
the coil in place (its important to wrap the ends directly across from each other;
balance is key in creating a good motor).
ELECTRICAL TECHNOLOGY LABORATORY 48
DJJ 2022 – ELECTRICAL TECHNOLOGYBasic DC Motor
6. The two ends that are trailing off the completed coil need to have the enamel
sanded off of the Copper Wire (this is extremely important because the more
enamel you remove the better electrical connection you are able to make between
the AA Battery and the Motor).
7. (This step is even more important than the first) Start by sanding only ONE SIDE of
the trailing ends of Copper Wire. (Only ONE SIDE)
8. The other trailing end of Copper Wire needs to have all of the enamel completely
sanded off. (Remember, the more wire you expose the better the connection)
ELECTRICAL TECHNOLOGY LABORATORY 49
DJJ 2022 – ELECTRICAL TECHNOLOGYBasic DC Motor
4.6 DISCUSSIONS
Part I. Fill in the blanks.
1. Motors are devices that convert ____________________________ energy into
_____________________________ energy.
2. The basic principle behind the simple DC motor is that wires that carry
_______________________ experience _________________________when placed
in regions of space that have _______________________________.
3. Only sections of wire that carry current in a direction _____________________to a
magnetic field experience forces.
4. The speed at which the rotor of a motor spins depends on three important factors:
________________________________, ______________________________, and
_________________________________.
5. The direction that the rotor of a motor spins depends on the
______________________________ rule.
(10 marks)
Part 2. Illustrate a complete basic motor.
(5 marks)
ELECTRICAL TECHNOLOGY LABORATORY 50
DJJ 2022 – ELECTRICAL TECHNOLOGYBasic DC Motor
4.7 CONCLUSION
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(10 marks)
4.8 REFERENCES
Book :
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Internet Address :
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(5 marks)
30Total :
ELECTRICAL TECHNOLOGY LABORATORY 51
DJJ2022 – ELECTRICAL TECHNOLOGY (LABORATORY RUBRIC)
Student’s Name : _________________________________
Date : ______________________
Group No :
Registration No :
Skills / Aspects/ Criteria
Excellent Average Weak Marks
4-5 2-3 0-1 PRAC 1 PRAC 2 PRAC 3 PRAC 4
A: Understanding the
material
Procedures are followed correctly
(choosing scale, parts, material)
Some procedures are followed and
some procedures are missing
(choosing scale, parts, material)
Major procedures are missing
(choosing scale, parts, material)
/5 /5 /5 /5
B:Ability to construct the
given circuit
Able to construct a circuit without
assistance
Able to construct a circuit with
slight assistance
Unable to construct circuit without
assistance./5 /5 /5 /5
C: Efficiency in taking data. All data are taken correctlyParts of the data are taken
correctly.
Most of all the data are taken
incorrectly./5 /5 /5 /5
D: Ability to relate practical
result with theories.
Able to relate the practical result
with the theories
Able to relate the practical with
some of the theories.
Unable to relate practical result
with theories/5 /5 /5 /5
Total /20 /20 /20 /20
Percentage % /100 /100 /100 /100
ELECTRICAL TECHNOLOGY LABORATORY 52
ELECTRICAL TECHNOLOGY LABORATORY 53
DJJ2022 – ELECTRICAL TECHNOLOGY (GENERIC SKILLS RUBRIC)
Student’s Name : _________________________________
Date : ______________________
Group No :
Registration No :
Skills / Aspects/ Criteria
Excellent Average Weak Marks
4-5 2-3 0-1 PRAC 1 PRAC 2 PRAC 3 PRAC 4
A : Disciplines
Dress Code
Lab Regulations
Meet all the criteriaMinor flaws to dress codes or lab
regulations Major flaws to all the criteria /5 /5 /5 /5
B : Punctuality Attend class on time. Late less than 10 minutes. Late more than 10 minutes. /5 /5 /5 /5
C : Pre-lab preparation
Pre-assisgnment
Bringing necessaryusable tools suchas laptop
Bringing Lab-sheet
Meet all the criteriaMinor flaws to pre-lab, assignment
& tools. Major flaws to all the criteria /5 /5 /5 /5
D : Practice Safety Procedures are followed correctly Some procedures are missing Major procedures are missing /5 /5 /5 /5
Total /20 /20 /20 /20
Percentage % /100 /100 /100 /100