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Page 1: Laboratory Workbook (Electrical Technology)

DJJ 2022 – ELECTRICALTECHNOLOGY

[Document subtitle]

[DATE]GRIZLI777

[Company address]

Page 2: Laboratory Workbook (Electrical Technology)

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

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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

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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

Page 5: Laboratory Workbook (Electrical Technology)

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

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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

Page 7: Laboratory Workbook (Electrical Technology)

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

ACV SELECTOR

TRANSISTORTESTING

RESISTORSELECTOR

NEGATIVE

TERMINAL (-VE)

CONNECTOR

POSITIVETERMINAL (+VE)CONNECTOR

DC mA SELECTORBUZZER

Page 8: Laboratory Workbook (Electrical Technology)

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

Page 9: Laboratory Workbook (Electrical Technology)

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.

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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

Page 11: Laboratory Workbook (Electrical Technology)

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

Page 12: Laboratory Workbook (Electrical Technology)

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

Page 13: Laboratory Workbook (Electrical Technology)

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

Page 14: Laboratory Workbook (Electrical Technology)

ELECTRICAL TECHNOLOGY LABORATORY 10

DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement

Page 15: Laboratory Workbook (Electrical Technology)

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.

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DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement

1.9.1.1 Series Connection

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ELECTRICAL TECHNOLOGY LABORATORY 13

DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement

1.9.1.2 Parellel Connection

Page 18: Laboratory Workbook (Electrical Technology)

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 : ____________________

Page 19: Laboratory Workbook (Electrical Technology)

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

Page 20: Laboratory Workbook (Electrical Technology)

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)

Page 21: Laboratory Workbook (Electrical Technology)

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)

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ELECTRICAL TECHNOLOGY LABORATORY 18

DJJ 2022 – ELECTRICAL TECHNOLOGYUnit Conversion& Measurement

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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 :

Page 24: Laboratory Workbook (Electrical Technology)

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

Page 25: Laboratory Workbook (Electrical Technology)

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 :

Page 26: Laboratory Workbook (Electrical Technology)

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

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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

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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 =____________

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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 =____________

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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 =____________

Page 31: Laboratory Workbook (Electrical Technology)

ELECTRICAL TECHNOLOGY LABORATORY 27

DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits

DRAW THE SERIES CIRCUIT CONNECTION ON THE PROTOBOARD:

(5 marks)

Lecturer’s signature: ____________________________ Date: _________________

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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

Page 33: Laboratory Workbook (Electrical Technology)

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 =____________

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DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits

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 =____________

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ELECTRICAL TECHNOLOGY LABORATORY 31

DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits

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 =____________

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DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits

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 : _________________

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DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits

2.6.2 Draw THE PARALLEL circuit connection ON THE PROTOBOARD:

(5 marks)

Lecturer’s signature: ____________________________ Date: _________________

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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)

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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)

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DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits

3. State the Ohm’s Law

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

(6 marks)

4. State the use of resistors.

________________________________________________________________________

________________________________________________________________________

(2 marks)

5. What is the effect of a resistor in a circuit?

________________________________________________________________________

________________________________________________________________________

(2 marks)

6. What is the connection between the resistors size and value of current flow?

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

(2 marks)

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DJJ 2022 – ELECTRICAL TECHNOLOGYElectrical Circuits

2.8 CONCLUSION

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

(6marks)

2.9 REFERENCES

Book :

_______________________________________________________________________

_______________________________________________________________________

Internet Address :

_______________________________________________________________________

_______________________________________________________________________

(2 marks)

70Total :

Page 42: Laboratory Workbook (Electrical Technology)

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.

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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

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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.

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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

Page 46: Laboratory Workbook (Electrical Technology)

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DJJ 2022 – ELECTRICAL TECHNOLOGY Transformer

3.6 QUESTION/DISSCUSSIONS

1. What is the windings ratio of the transformer?

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

(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

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DJJ 2022 – ELECTRICAL TECHNOLOGY Transformer

1. Draw the input and output waveform of the transformer.

Input voltage

(5 marks)

Output voltage

(5 marks)

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DJJ 2022 – ELECTRICAL TECHNOLOGY Transformer

3.7 CONCLUSIONS

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

(5 marks)

3.8 REFERENCES

Book :

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

Internet Address :

___________________________________________________________________________

___________________________________________________________________________

(5 marks)

(2 marks)

30Total :

Page 49: Laboratory Workbook (Electrical Technology)

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

Page 50: Laboratory Workbook (Electrical Technology)

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

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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).

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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)

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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)

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ELECTRICAL TECHNOLOGY LABORATORY 50

DJJ 2022 – ELECTRICAL TECHNOLOGYBasic DC Motor

4.7 CONCLUSION

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

(10 marks)

4.8 REFERENCES

Book :

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

Internet Address :

___________________________________________________________________________

___________________________________________________________________________

(5 marks)

30Total :

Page 55: Laboratory Workbook (Electrical Technology)

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

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ELECTRICAL TECHNOLOGY LABORATORY 52

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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