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Laboratory Manual

Experiments in

CircuitAnalysis

Engr Khawar JavedAsst Prof of Electrical Engineering

U n i v e r s i t y o f S o u t h A s i a

L a h o r e , C a n t t

1



Electric Circuit Manual, presents a series of projects in which a through,

practical investigation is made or basic electronics component/circuits and

the principles underlying their behavior.

The projects are designed to be correlated with a second course and the

content in each based upon concepts developed in preceding projects. The

projects were planned with the following objections.

1. To have all the essential hardware assembled on each panel so that

students need not concern themselves with time wasting procurement

to parts needed for given experiment.

2. To devise projects that verify the principles of electronics’ theory and

to include self-teaching features in the projects whereby the student

can observe a step-by-step pattern or structure of related ideas. This

cultivates the analytical powers of the students.

3. To present each project with introductory information of a theoretical

nature essential for an insight into the manner in which theory and

practice are bridged.

At the conclusion of each project the teacher should require the student to

write a brief report regarding the electrical principal or law under

discussion, and indicate the particular aspects of the project which revealthis law to him. it is also suggested that in the preparation of such a report

the student should include a parts list of the components involved. This

will develop a familiarization with the standard nomenclature associated

with typical components.

I n t r o d u c t i o n

2



This Electric circuit Laboratory Manual is suitable for one of academic

term of study in Electronics and goes along with the second course of

Electronics.

This Laboratory manual is the result of the dedication and encouragement

of many individuals. Our sincere and heartful appreciation goes to all of

them.

First of all I would like to thanks Chairman of USA Mr Mehmood Sadiq

and Professor Engr Dr Junaid Zafar (Dean of Electrical Engineering,

University of South Asia, Lahore Cantt), The most knowledgeable and

experienced person in the field of Electrical Engineering. Also I would

like to express our sincere thanks to Asst Prof Manzar Ahmad (HOD of

Electrical Engineering, University of South Asia, Lahore Cantt) for this

helpful suggestion on the organization of the laboratory manual.

In additional, The following Professors and Students found errors whileusing the laboratory manual in it’s pre-publication from in their Analogue

Electronic Circuit ,and we thank them sincerely ,Lecture of Electrical

Engineering Mr Naveed Khalid(USA) and Mr Waqas Arif(USA).

Muhammad Ali Johar (USA), Idrees sohail (USA), Kamran Tariq

(USA),Usman Waheed(USA) are brilliant students of Circuit Analysis

made many valuable suggestions.

We enjoyed writing this laboratory manual, and hope you enjoy reading it

and using it for your course and projects, please let us know if you have

any suggestions or find any error.

Author: Engr Muhammad Khawar Javed

[email protected]

A c k n o w l e d g m e n t

3



1. Note the location of the Emergency Disconnect (red button near thedoor) to shut off power in an emergency. Note the location of the

nearest telephone (map on bulletin board).

2. Students are allowed in the laboratory only when the instructor is

present.

3. Open drinks and foods are not allowed near the lab benches.

4. Report any broken equipment or defective parts to the lab instructor.

Don’t open, remove the cover, or attempt to repair any equipment.

5. When the lab exercise is over, all instruments, except computers,must be turned off. Return substitution boxes to the designated location.

Your lab grade will be affected if your laboratory station is not tidy

when you leave.

6. University property must not be taken from the laboratory.

7. Don’t move instruments from one lab station to another lab station.

8. Don’t tamper with or remove security traps, locks, or other securitydevices. Don’t disable or attempt to defeat the security camera.

9. ANY ONE VIOLATING ANY RULES & REGULATIONS MAY

BE DINED ACCESS TO THESE FACULTIES.

Safety Rules and Operating Procedures

4



The laboratory notebook is a record of all work pertaining to theexperiment. This record should be sufficiently complete so that you or

anyone else of similar technical background can duplicate the

experiment and data by simply following your laboratory notebook.

Record everything directly into the notebook during the experiment.

Don’t use scratch paper for recording data. Don’t trust your memory to

fill in the details at a later time.Organization in your notebook is important. Descriptive headings

should be used to separate and indentify the various parts of the

experiment. Record data in chronological order. A neat, organized andcomplete record of an experiment is just as important as the

experimental work.

1. Heading: The experiment identification (number) should be at

the top of each page. Your name and date should be at

the top of the first page of each day’s experimental work.

2. Object: A brief but complete statement of what you intend to find

out or verify in the experiment should be at the beginningof each experiment.

3. Diagram : A circuit diagram should be drawn and labeled so thatthe actual experiment circuitry could be easily duplicated at any time inthe future. Be especially careful to record all circuit changes made

during the experiment.

4. Equipment List: list those items of equipment which have a direct

effect on the accuracy of the data. It may be necessary later to locate

specific items of equipment for rechecks if discrepancies develop in

the results.

5. Procedure: In general, lengthy explanations of procedures are

unnecessary. Be brief. Short commentaries alongside the corresponding

data may be used. Keep in mind the fact that the experiment must be

reproducible from the information given in your notebook.

6. Data: Think carefully about what data is required and prepare

suitable data tables. Record instrument readings directly. Don’t use

calculated results in place of direct data; however, calculated results

GUIDELINES FOR

LABORATORY NOTEBOOK

5



may be recorded in the same table with the direct data. Data tables

should be clearly indentified and each data column labeled and headed

by the proper units of measure.

7. Calculations: Not always necessary but equations and sample

calculations are often given to illustrate the treatment of the

experimental data in obtaining the results.

8. Graphs: Graphs are used to present large amounts of data in a

concise visual form. Data to be presented in graphical form should

plotted in the laboratory so that any questionable data points can be

checked while the experiment is still set up. The grid lines in the

notebook can be used for most graphs. If special graph paper required,affix the graph permanently into the notebook. Give all graphs a short

descriptive title. Label and scale the axes. Use units of measure. Labeleach curve if more than one on a graph.

9. Results: The results should be presented in a form which makes

the interpretation easy. Large amounts of numerical results are

generally used for small amounts of results. Theoretical and

experimental results should be on the same graph or arrange in the

same table in a way for easy correlation of these results.

10. Conclusion: This is your interpretation of the results of the

experiment as an engineer. Be brief and specific. Give reasons for

important discrepancies.

6



Electric CircuitTable of Contents [DC PART]

S. No

Description Page No. Date of Completion

1.

2(a).

2(b).

3.

4(a).

4(b).

5.

6(a).

6(b).

6(c).

Introduction to the Lab

apparatus & resistance

color code.

To Measure the

CURRENT.

To Measure the

VOLTAGE.

To verify the Voltage

Rises & Voltage Drops.

To verify experimentally

the relationship b/w I, V

& R in a circuit.

To verify the Ohm’s

Law.

To verify Ohm’s Law in

Parallel circuit.

Voltage Division.

Current Division.

KCL.

6

10

15

20

24

28

32

44

49

53

7



1.

2.

3.

4.

5.

6.

7.

Measuring Ac Voltage.

Using an Oscilloscope

Oscilloscope.

Combining Resistors and

Capacitor.

RC wave Shaping.

Capacitive voltage

division and filtering.

LC filters.

Table of Contents [ AC PART]

8



Experiment – 1

Introduction to the Lab apparatus.

Introduction to Laboratory Apparatus :

This experiment will provide exposure to the various test equipment to be

used in subsequent experiments. A primary purpose of this lab course is for

you to master the use of electronic test equipment. The devices we will be

using include DC power supplies, breadboards, digital multi meters”DMM”,

oscilloscope and a function generator.

1. Introduction to resistor color code:

A resistor is a two-terminal electrical or electronic component that resists an

electric current by producing a voltage drop between its terminals in

accordance with Ohm's law: The electrical resistance is equal to the voltage

drop across the resistor divided by the current through the resistor. Resistors

are used as part of electrical networks and electronic circuits. Most axial

resistors use a pattern of colored stripes to indicate resistance. The resistors

in the lab have 4 bands but the resistors with six bands are also available. An

example given below describes how to calculate the resistance from color

bands.R = V / I

2. To determine the value of resistance from its color

code.

9



10



3. To determine the value of resistance from its color

code.

The first two bands on a resistor are always the first two digits of the

resistance. The third band contains the third digit, but may not be included in

some resistors. After the first two or three digits comes the multiplier. This

number represents the power of 10 that is then multiplied with the first digits

to give the resistance. Note that a gray or white band used as the multiplier has two possible meanings. The bands usually represent 10^8 and 10^9, but

in some oddballs they may actually mean 10^-2 and 10^-1. More often you

will see a silver or gold stripe used to represent 10^-2 and 10^- 1. The next

band, and most often the last, is the tolerance band. This band indicates what

the actual value of the resistor may be. The actual resistance of the resistor

must be within this percentage of the rated value, or else it is considered no

good. The reliability and temperature coefficient bands are not included on

many resistors, and they will never both be on the same resistor. A reliability

band indicates the failure rate per 100 hours. The temperature coefficient band specifies the maximum change in resistance with change in

temperature, measured in parts per million per degree Centigrade (ppm/°C).

You will see reliability bands more often on older resistors and temperature

coefficient bands on newer ones. If a resistor has four bands total (or three

bands if the tolerance is ±20%), it will contain two digits, a multiplier, and a

tolerance band. If a resistor has five bands and is a newer one, it most likely

11



has three digits, a multiplier, and a tolerance band. If an older resistor

contains five bands, it is probably one containing two digits, a multiplier,

tolerance, and reliability band. You will probably only ever see newer

resistors with six bands, and they will include three digits, multiplier,

tolerance, and temperature coefficient bands. Let's say you have a resistor

with a yellow, violet, red, and gold band. The first band represents the first

digit, and a yellow band means 4, so the first digit in the value of

the resistor is 4. The next band is violet; meaning 7 is our next digit. The

next band is our multiplier, and will tell us to what power of 10 we must

multiply the first two digits by. A red band in the multiplier means 10^2, so

to get the value of the resistor we must multiply 47 by 10^2. This gives us

4,700 ohms, or 4.7 kilo ohms. The last band is the tolerance, a gold band

meaning the actual value must be ±5% of the value on the resistor. So the

actual value of the resistor may be anywhere from 4,465 ohms to 4,935

ohms. If we were to then measure the resistance of the resistor with a DMMand found that it was <4,465 ohms or >4,935 ohms it would be defective.

4. To measure a resistor using multi-meter. Your instructor will give you 5 resistors of various values and tolerances.

Examine each one and determine its resistance and tolerance according to its

color code. Record the color bands, the coded resistance value and the

tolerance in following table.Resistor Color Code(Record

four color bands)

CodedValue

()

Tolerance(%)

Max. CodedResistance

()

Min. CodedResistance

()

MeasuredValue using

DMM( )

Error (%)

Red-violet-Orange-Silver

27K 10% 27k+2.7K=2 27K2.7K=24.3K 25.1K 7.04

12



Experiment 2(a)

To Measure the CURRENT.

Equipment & Component:

1. Digital Multi-meter 2. 1-foot of#22 copper wire

3. 1-foot of #22 nichrome wire

4. 15ohm 5% 1/2 watt resistor

5. Bread board

6. Power supply

PROCEDURE :1. Construct the circuit shown in figure (below) using 1-foot of #22

copper wires.

2. Connect the positive lead of your digital multi-meter to the end of the

copper wire at point A in the figure above. Leave the negative end of your

multi-meter connected to the GND terminal.

3. Set up your multi-meter range to 500 mA and observe the current as

measured by the multi-meter. Record your measurement: _______mA.

4.Replace the 1ft copper wire in your circuit with 1ft of nichrome wire andrepeat steps(2) and (3) and record your measurement: __________mA.

5. Is the current measured in step (4) greater than current observed in step (3)

of the experiment? _________

CONCLUSION :

13



The current will travel at a different rate through different materials. The

copper wire allows electrons to pass at a higher rate than the nichrome wire.

Therefore, the copper wire is a better conductor than the nichrome wire. It

could also be stated that nichrome wire has a higher resistivity or resistance

than a copper wire of the same length and gauge.

Observations:

Conclusions:

Registered No _______________

Teacher’s Initial ______________

Experiment 2(b)

14



To Measure the VOLTAGE Objective:

To measure voltage using digital Multi-meter.

Equipment:1. Digital Multi-meter .

2. Power supply.

Procedure:

1. Set your Multi-meter to measure 15 volts DC.2. Connect the positive lead of your multi-meter to the positive

of your power supply. Connect the negative lead of your multi-

meter to the ground terminal.

3. Switch your meter to measure 5 volts DC. Record your

measurement _______V.

4. Switch your meter to measure 10 volts DC. Record your

measurement _________V.

5. Measure the voltage at 15V and record your measurement ___________________V.

6.Measure the voltage between the negative and ground

terminals with the voltage control set to the following positions.

15



Record the measured voltages in the spaces provided in the

figure below.

Discussion:-In this experiment you gained some practice using multi-meter (voltmeter).

First you measured the voltages produced by the positive power supply. Thisvoltage can be set to any value from +1volt to 15 volts. Next you measured

the voltages produced by the negative power supply. This voltage can be set

to any value from -1V to -15V

Observations:

(-)Voltage Control SET

TO:

Voltage Measured

(-) 1

(-) 5

(-)10

(-)15

Conclusion:



Experiment – 3

16



To verify the Voltage Rises & Voltage DropsObjective :To verify that the sum of the voltage drops is equal to the sum of the

voltage rise.Equipment& Component:1. Digital multi-meter 2. 1-1kohm 1% 1/2w resister

3. 2-1kohm 5% ½ w resisters(brown, black, red, gold)

4. Slide switch(60-2)

5. Soldering iron and solder

6. Bread board

7. Power supply.

Procedure:

1. Connect the circuit shown in figure below.

2. Connect your Multi-meter between the positive and ground

terminals and adjust the voltage control for exactly 9v.) Operate

the slide switch. Does the voltage disappear when current stops

flowing------------? Is this a voltage rise or a voltage drop?

3. Connect the Multi-meter across R1 and measure its voltage

drop--------------v.

17



4. Measure the voltage drop across R2-------------------------------

v.

5. Measure the voltage drop across R3-------------------------------v.

6. Add the three voltages drop together---------v. Is this the same

voltage rise from step2?

Observations:

1. The voltage across the resistor exists only when current flowsand therefore, is a voltage drop.

2. Voltage drop across R1+ Voltage drop across R2+voltage drop

across R3=Voltage rise.

Conclusion:



18



Experiment 4(a)

To verify experimentally the relationship b/w I, V

& R in a circuit.Objective :

To verify experimentally, the relationship between current,

voltage and resistance in a circuit

Equipment & Components:

1. DMM.

2. Power Supply

3. Resistors.VOLTAGE :This is sometimes called potential difference or P.D.Here is some

typical values:

70mv The voltage across the inside outside of a

human nerve.

1.5v The voltage of a walkman battery

6v The voltage of a moped battery12v The voltage of a car or motorcycle battery

24v The voltage of a 50 seater coach battery

110v Mains voltage in the USA & some continental

countries.

240v Nominal mains voltage in the UK

Thousands of volt Voltages in amateurs’ antennas whilst

transmitting.

As you can see, there is a lot of difference between the voltages inour nerves and muscles and the voltages in the mains power

supply. It does not make a lot of sense to put your fingers in the

mains power sockets! 1.5 volts might be enough to light up a small

tent with a torch, but not enough to light up your living room.

19



1mv (one millivolt) is 1 thousandth of a volt.

1Mv (one Megavolt) is 1 million volts.

Batteries, the mains, dynamos and electrical generators provide the

energy to force electrons around electric circuits. The bigger thevoltage is, the greater the "force" making electrons go round a

circuit. You can think of it as being like a hill: if you fall down the

hill you could roll to the bottom. The steeper the hill is the quicker

you will roll down it.

CURRENT:Current is measured in amperes or amps for short. We use the

symbol "I" in the formula to represent current. (The reason for using "I" rather than "C", is that "C" is already used for something

else.) The kind of current flowing in our nerves and muscles is

only a few micro amps: the currents flowing in the mains might be

as much as 13 amps.

RESISTANCE:Resistance is to do with how easy it is for the electric current to

flow through a material, e.g. a piece of copper wire. Although your physics teacher will tell you that copper is a very good conductor

of electricity, it does have a measurable resistance. Some materials

have virtually no resistance when they are cooled down to absolute

zero, they are called super conductors. Mercury will do this.

Materials like plastic, wood, polythene, ceramics and rubber have

very high resistances so that it is almost impossible for electric

currents to flow through them. These materials are called

insulators. They may not be perfect.

Materials like copper, silver, and gold have very low resistances. In

fact all metals will conduct electricity. They are called conductors.

Even so, they do have some resistance to the flow of electrons

through them. A perfect conductor is called a superconductor, it

has zero resistance; very cold mercury acts as a superconductor.

Resistance is measured in Ohms.

20



Ohm's Law says that there is a relationship between these three

factors. So if you know two of the values you can easily work out

the third one.

V=IxR

I=V/R R=V/I

Procedure:The purpose of this laboratory is to practice making voltage,

current, and resistance measurements and become acquainted with

Ohm’s Law. Refer to the following circuit.

Build the circuit as shown. Use your regulated power supply to

generate 10 V and connect it to the 2.2 k and 4.7 k resistors as

indicated. Measure the voltage across each resistor and the current

through the circuit (hint: make sure your millimeter's leads are

connected properly for a given measurement).

V2.2 k = __________

V4.7 k = __________

I = __________

Calculate the theoretical resistance of each resistor by Ohm’s Law.

R2.2 k = V2.2 k / I = __________

R4.7 k = V4.7 k / I = __________

21



Now measure the actual resistance of each resistor using your

multi-meter

R2.2 k(actual) =__________

R4.7 k(actual) =__________

Observations:

1) Consider the circuit shown in fig.c for the fixed values of resistances calculate current by increasing voltage. Increase

the voltage from 10 to 18 V.

Voltage(V) Current(A)

10

11

12

13

14

15

16

17

18

Draw the graph between Current (I) and Voltage (V):

22



2) Now fix the voltage and start increasing resistance. (Anyone of the resistance).Fix the voltage at 10V.

Resistance(ohm) Current(mA)

23



Draw the graph between current and resistance:

3) Now make the current constant (1.45 mA) and change the

resistance and voltage to make the current 1.45mA.

Voltage(V) Current(mA)

24



Draw the graph between Voltage and Resistance:

Conclusion:



25



Experiment 4(b)

To verify Ohm's Law.

Equipment & Components:

1. DMM.

2. Power Supply

3. Resistors.

OHM'S LAW :Ohm's law, named after its discoverer, states that the potential

difference V between the ends of a conductor or resistor R and the

current I flowing through R are proportional at a giventemperature:

In other words where V is the voltage and I is the current; the

above equation yields the proportionality constant R, which is the

electrical resistance of the device. The law is strictly true only for

resistors whose resistance does not depend on the applied voltage,

which are called ohmic or ideal resistors or ohmic devices. Ohm's

law is never completely accurate, if R is assumed to be constant,for "real world" devices, because no real device is an ohmic device

for every voltage and current – at some level, the device will open

or short, for example, by burning up or arcing. Moreover,

temperature is an important factor determining the accuracy of

Ohm’s law. When the temperature of the metal increases, the

26



collisions between electrons and atoms increase, so that when a

substance heats up because of electricity flowing through it (or by

whatever heating process), the resistance will increase.

The relation V / I = R even holds also for non-ohmic devices, but

then the resistance R depends on V and is no longer a constant. Tocheck whether a given device is ohmic or not, one plots V versus I

and compares the graph to a straight line through the origin.

Blue line is ohmic, red line is non-ohmic. Yellow is a semi-

conductor.

So, from above discussion we get to know that Ohms law is about

three things Voltage, Current and Resistance.

Conclusions:



27



Experiment – 5

To verify Ohm’s Law in Parallel circuit.

Purpose:

To prove that ohm’s law applies to parallel circuits.

Equipment:

1. Bread Board.

2. Multi-meter.3. Power supply.

4. 2.1k ohm resistor.

5. 2.10k ohm resistor.

Procedure:

1. Construct the circuit shown in figure below.

28



2. Connect your multi-meter (voltmeter) from the GND terminal to

the POS terminal on the terminal and adjust the +voltage to exactly

+10volts.

3. Connect your multi-meter (ohm meter) to the circuit shown

above between point C and ground. The current through the circuitis ____________mA.

4. Now using the voltage applied to the circuit and the total current

through the circuit, use ohm’s law to calculate the total resistance

of circuit--------ohms.

5. Calculate Resistance of the complete circuit Rt using the

equations. RT _______ Ohm. Is there any difference between the

total resistance calculated in step (4) and the total resistance

calculated in step (5)? Yes or NO _________.6. Use the nominal value of resistor R1 1000ohms and the current

measured in step 3 to calculate the voltage dropped across the R1.

The calculated voltage drop is _________V. Now using the multi-

meter, measure the voltage across R1 the measured voltage is

________V.

7. Measure the voltage drop across the parallel network consisting

of resistors, R2 (10k), R3 (10K), and R4 (1K). The voltage drop is

__________V.

8. Using the voltage drop measured across the parallel network and

the nominal value of resistor R2, R3, and R4 determine the current

through each of the branches. I=________mA, I2=______mA,

I3=________mA. Is total current approximately the same as the

sum of the three calculated branches? Yes or NO_______

Conclusion:



29



Experiment 6(a)

Voltage Division.

Objective:To verify experimentally Voltage Division.

Equipment:

1. DMM.

2. Power Supply.

3. Resistors.

4. Jumpers.

5. Cutter

Introduction:A voltage divider referenced to ground is created by connecting

two resistors as shown in the following diagram:

Vout = R 2 / R 1 + R 2 x Vin

It may be useful to note that R1 and R2 may each comprise

many resistors in series.

As a simple example, if R1 = R2 then

Vout = ½ x Vin

30



OBSERVATIONS AND CALCULATIONS:-

1. Use your regulated power supply to generate 6 V and connect it

to the circuit as shown. Measure V, V, I, I, and I.

V 2= __________

V3 = __________

V4= __________

I = __________

I 1= __________

I2 = __________

I3= __________

2. Does I 1+ I2 + I3 =I? Why or why not?

Conclusion:



31



Experiment 6(b)

Current Division.Objective:

To verify experimentally Current Division.

Equipment:1. DMM.

2. Power Supply.

3. Resistors.

4. Jumpers.

5. Cutter

Introduction:

The current divider rule (or CDR) is used to find the electrical

current flowing through impedance or other circuit when it is

connected in parallel with impedance. It is similar in form to the

voltage divider rule. The key difference, however, isthatthenumerator of the equation is the impedance you are not

considering.

If two or more impedances are in parallel to each other, the current

that enters them will be split between them in inverse proportion to

their resistance (from Ohm's law). It also follows that if the

impedances have the same value the current is split equally.

32



This is a general form of the current divider.

Note that Rt is the parallel resistance hence the reciprocal of each

resistor must be added.

OBSERVATIONS AND CALCULATIONS:-

1. Find out the values of VAB, V3 and VCD.

2. VAB= ________

3. V3= ________

4. VCD= ________

33



5. See that sum of the three voltages is equal to the supplied

voltage.

6. Measure V1, V2, V3, V4, and V5.

V1 = __________

V 2= __________

V 3= __________

V 4= __________

V 5= __________

V 6= __________

7. Does V1 + V3 = V? Why or why not?Does V1 + V4 + V5 + V6 = V? Why or why not?

8. Does V4 + V5 + V6 = V3? Why or why not?

Conclusion:Registered No _______________


34



Experiment 6(c)

Kirchoff's LawsObjective:To verify Kirchoff's Laws.

Equipment & Components:1. DMM.

2. Power Supply.

3. Resistors.

4. Jumpers.

5. Cutter

Introduction to Kirchhoff's Current Law :

This fundamental law results from the conservation of charge. It

applies to a junction or node in a circuit -- a point in the circuit

where charge has several possible paths to travel.

35



In Figure 1, we see that IA is the only current flowing into the

node. However, there are three paths for current to leave the node,

and these current are represented by IB, IC, and ID.

Once charge has entered into the node, it has no place to go except

to leave (this is known as conservation of charge). The total chargeflowing into a node must be the same as the total charge flowing

out of the node. So, a circuit

IB + IC + ID = IA

Bringing everything to the left side of the above equation, we get

(IB + IC + ID) - IA = 0

Then, the sum of all the currents is zero. This can be generalized as

follows

Conclusion:



36



AC PART

Experiment – 1

Measuring Ac Voltage.Objective:-

1. To demonstrate how an AC voltmeter is used to measure

voltages.

2. To demonstrate the relationships between AC voltages

and current, in series resistive circuit.

Equipment & Components:1. Bread board.

2. Power Supply.3. 1-470ohm, ½watt resistor (Yellow-violet-brown).

4. 1ohm, ½ watt resistor (brown-black-red).

5. Digital multi-meter.

Procedure:-1. Construct the circuit shown in Figure below.

2. Measure the 15volt AC with your multi-meter to determine is

exact value------V.

3. Measure the voltage across R1 with your multi-meter.

V1= ---------Volts.

4. Now measure the voltage across R2 with your multi-meter.

37



V2= -------------Volts.

5. Add the individual voltages (V1 & V2) that you measured in

the two previous steps. The sum of the two voltages is.

V1+V2= ----------Volts.

6. Use Ohms law to calculate the current in the circuit. First, find the

total resistance (RT). RT= R1+R2 or---------------ohms.

7. Use Ohm’s law to calculate the voltage across R1.

V1=IxR1=-----------Volts.

8. Use Ohms law to calculate the voltage across R2.

V2= IxR2 or------------Volts.

9. Compare the V2 value measure in step 4 with the V2 value

calculated in step 10. The V2 value in step4 is;

A. Approximately equal to the V2 value in

B. Much higher than the V2 value in step 10.

C. Much lowers than the V2 value in step 10.

Conclusion:

Use data and conclude your result. Use separate sheet.



38



Experiment – 2

OscilloscopeWhat is an Oscilloscope?1. One of the instruments which are very important for making

electrical measurements in the circuits which you will learn is the

oscilloscope.

2. The oscilloscope is capable of automatically displaying is ac or

dc voltage graphed versus time as shown in figure below.

3. An oscilloscope is an instrument which converts electrical

signals to visual wave forms on a screen.Basic Functions of an OscilloscopeAn oscilloscope performs three basic functions.

a. Waveform observation.

b. Amplitude measurement.

c. Measurement of time.

There are many different oscilloscopes in use today. However,

there are many basic controls and functions common to all scopes.

The scope can be divided into two 2 major segments:-a. Cathode Ray Tube (CRT).

Controlling units.

Cathode Ray Tube (CRT)The CRT is the heart of the scope. it consists of 3 major parts

a. Electron gun.

b. Deflection system.

c. A screen.Electron Gun:-It is located at the rear end of the CRT. Its job is to emit a narrow

stream of electrons.

39



Digital Multi-meter: - A DMM is used to measure the voltage,

current or resistance is an electronic circuit. From the ESCORT-

178DMM available in your lab, one can measure AC voltage, DCVoltage, Resistance, Capacitance, AC current, and DC current.

Oscilloscope: - The main function of the oscilloscope is to view

and measure AC waveform. Most oscilloscopes have a dual trace

capability, which means they can display two waveforms at the

same time.

Power Supply: - A power supply is a unit capable of supplying

d.c. voltage and current to electronic circuit under test, Modern

power supplies have regulated outputs. This means that their outputvoltage does not fluctuate as the load current varies.

Function Generators: - A function generator is a piece of test

equipment capable of producing a number of different output

waveforms, (sine and square waves at frequencies from 200Hz to

20KHZ. All function generators have controls to adjust the

amplitude frequency and shape of the output waveform.

Solder: - Solder is a metal alloy that use to join electronic

components together There are several varieties of solder available, but for electronic hand soldering 60/40 rosin core solder is used.

The 60/40 ratio refers to mixture containing 60% tin and 40 %

lead.

Soldering irons:- In any kind of soldering the primary

requirement, beyond the solder itself is heat can be applied in a

number of ways-conductive(e.g. soldering iron etc.) convective

( hot air) or radiant (IR) they are mainly conserved with the

conductive method, which uses a soldering iron. A pencil solderingiron (20-40 watt) is usually preferred for most electronics circuit

repairs.

Deflection System:-

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The electron beam travelling toward the screen passes through the deflection

system. The deflection system consists of four (4) deflection plates as shown

in figure below.

(A). If a voltage is applied across the vertical deflection plates asshown below the electron beam moves up words. If the polarity

applied to the plates in reversed, the beam moves downward.

(b). If the voltage is applied across the horizontal deflection plates

as shown below, the electron beam will travel from left to right. If

the polarity applied to the deflection plates is reversed, the beam

moves from right to left.

(c) If voltages are applied to the vertical & horizontal deflection plates simultaneously, the beam moves vertically and horizontally

at the same time diagonally.

(d) If no potential is applied to the plates, the beam returns to the

centre of the tube. This was the original position.

The Screen:-

The third and the remaining of the CRT is the screen. After the beam is emitted and travels through the deflection system, it strikes

the screen at a point determined by the deflection plates. The inside

surface of the screen is coated with a phosphor material which has

the ability to emit light after being struck by the electrons.

CONTROL CIRCUITS:-The control circuits are electronic circuits that perform several

functions. They cause the CRT to (i) emit electrons, (ii) regulatehow many electrons make up the beam current and control the

direction of the beam of electrons. The controls are at the front

panel of the scope.

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Screen Graticule:-

To the left of all of these controls, of the scope is the CRT. Notice

that the screen has been marked into eight vertical division and ten

horizontal divisions. Each division has been further marked off into

five equal increments. Each increment represents two-tenths (2/10)of one division. This scale is called graticule.

Equipped with a graticule, the oscilloscope provides an electronic

graph of Voltage against time. It essentially is a calibrated scale

with the vertical divisions of the graticule representing voltage

values and the horizontal divisions representing increments.

Determination of the Voltage amplitude & period of the

waveform

E= (number of divisions) x (volts per divisions)T= (number of divisions) x (seconds per division)

Example Given: Volts/division=2V

Time/division=10micro seconds

Wave Type=Square wave

Amplitude= 4 divisions

Y axis= the period of waveform is contained within 8

horizontal divisions.

Find: - Epp, FP, Erms, T, f Solution: - EPP= (4division) (2V/division) =8V

EP = (1/2 (8V) =4V

Erms= (0.707) (Ep) = (0.707) (4) = 2.83V

T= (4division) (10micro second) /division) =

40micro second

F= 1/T = 1/40 = 25Khz.

Conclusion:Use data and conclude your result. Use separate sheet.



42



Experiment – 3

Using an OscilloscopeObjective:-

1. To use the oscilloscope to measure an AC wave from

amplitude and period.

2. To observe the phase relationship between voltage

and current in an AC resistive circuit.

3. To observe the shape of sine waves and square

waves.

4. To observe and calculate peak, peak, effective, and

Peak-to peak Ac voltages.

5. To measure DC voltages with an oscilloscope.Equipment & Components:

1. Bread board.

2. Power Supply.

3. Freq Generator.

4. Oscilloscope.

5. 1-100ohm, ½ watt resistor (brown, black, brown).

6. 1-100, ½ watt resistor (brown, black, red).

Procedure:-Set the oscilloscope controls as follows:-

1. Turn the INTENSITY control to mid-range.

2. Set the TRIGGER SOURCE switch to the INT position.

3. Set the TRIGGER MODE switch to the AUTO position.

4. Set the TIME/CM control to the 2ms position and the

SWEEP/VAR to CAL.

5. Set the HORIZ POS control to mid- range.

6. Set the AC-GND-DC switch to the GND position.7. Set the VOLTS/CM control to 5 and the Variable to CAL.

8. Set the VERT POS control to mid range.

9. Connect the oscilloscope to the proper power source.

10. Turn the POWER switch ON.

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11. Allow the oscilloscope to warn up for one minute, and

then adjust the VERT- POS and HORIZ POS controls to

centre the sweep on the scope.

12. Adjust the FOCUS control for a sharply focused

presentation.13. Set the AC-GND-DC switch to the AC position.

14. Attach the probe to the VERTICAL INPUT.

15. Construct the circuit shown in figure e-2.1

16. Ensure that the TIME/CM control is set to the 2ms-per-

centimeter position.

17. Set the VOLTS/CM control to a position that allows the

entire waveform to be displayed on the oscilloscope. A total

deflection of form four to six centimeters is desirable for mostamplitude (vertical) measurements. The Y1 switch should be

set to 5V/CM.

18. Make sure that both the SWEEP/VAR and the

VARIABLE control are in the calibrate position (usually fully

clockwise).

Conclusion:

Use data and conclude your result. Use separate sheet.



44



Experiment – 4

Combining Resistors and Capacitor Objective:-

1. Demonstrate the characteristics of a series RC

network.

2. To show the effect of capacitors in series and

parallel.


2. Power Supply.


4. 1-0.039uf capacitor.5. 1-0.1uf capacitor.

6. 1-0.4uf capacitor.

7. 1-4.7k ohm ½ watt resistor.

Procedure:- 1. Construct the circuit shown in figure E3-1.

45



2. Using your multi-meter measure the AC voltage source

which is connected to the circuit. The AC line voltage

------------ Volts.

The Voltage you have measured is expressed as a/an; Avg /

eff /peak-value------.3. With the resistor and capacitor values given and the voltage

measured in step2, compute and record the following;

Xv-----------ohms; Z=-----------ohms; 1= ----------Amperes,

VR=-------------volts, Vc=--------volts, -----------degrees,

PT= -----------watt.

4. Measure the resistor and capacitor voltages in the

experimental circuit and record your measurements in the

spaces provided; VR= -------------volt& Vc= --------volts. Areyour calculated and measured values equal=?

Yes or no ________.

5. Add the resistor and capacitor voltages that you measured

and record the sum in the space provided below;

------------ Volt.

Does the sum of the resistor and capacitor voltage equal the

applied voltage that you measured in step2?

Yes or No. _________.

6. Using the measured resistor voltage and the resistance,

compute circuit current I------------Ampere.

Does the computed circuit current in step 6 equal with the

current value calculated in step3?

Yes or No--------------------- if no why-----------------------------

7. Construct the circuit shown in figure E3-2.

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8. Compute the total circuit capacitance using the rules for

parallel capacitance.

CT--------------------------------------uF.

9. Apply power to the experimental circuit. Using your ACvoltmeter, measure the voltage across the resistance and the

voltage across the parallel capacitor combination.

VR=-----------volts. VC=-------------volts.

10. Using the capacitor voltage you measured in step 9 above

and the circuit resistance; compute the current floating in the

circuit. I= ------------amperes.

11. Using the capacitor voltage you measured in step 9 and

the current you computed in step 10, compute the capacitivereactance in the circuit Xc= -----ohms.

12. Knowing the capacitive resistance and the frequency of

the applied voltage, you can now calculate the total circuit

capacitance. CT= ----------------uf.

How does your computed value of capacitance obtained in

step 2 compare with the value obtained from measurement in

step 12? -----------------------------------------.

Agree/Disagree


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14. Find the total capacitance of the series circuit.

CT= ----------------uf.

15. Apply voltage to your experimental circuit. Measure the

resistor and capacitor voltages with your AC voltmeter,

VR= -------------volts. Vc=--------------------volts.16. Using the measured resistor voltage and the resistance

value, compute circuit current; I. ----------------amperes.

17. Using the measured capacitor voltage and the current you

computed in step 16, find the total capacitive resistance in the

circuit.

Xc= -------------------ohms.

18. using your computed value of capacitive reactance and the

frequency of the applied AC voltage, compute the total circuitcapacitance.

CT= ----------------uf.

Conclusions:



48



Experiment – 5

RC wave ShapingObjective:-

1. To examine the operation of an RC coupling circuit.

2. To examine the operation of a differentiator circuit.

3. To examine the operation of an integrator circuit.


2. Power Supply.

3. Digital multimeter.

4. Oscilloscope with probe.

5. Frequency generator.6. 1-0.01uf capacitor.



Procedure:- 1. Construct the circuit shown in figure E6-1. Turn on the circuit

and set the generator frequency to 1000Hz.

2. Set the potentiometer fully clockwise. Using the oscilloscope,view the rectangular wave input to the RC circuit. Draw two cycles

of the waveform in Figure e6-2A. What is the time of one cycle of

the 1000Hz square wave? ------------- Microseconds. What is the

time of the positive portion of the waveform? ------------

Microseconds.

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3. Set the 100k ohm potentiometer fully counter clockwise. With

an oscilloscope observe the output. Draw two cycles of the output

waveform in figure E6-2B. How much resistance is now in series

with the capacitor? -------------- Ohms.

What is the RC time constant ----------------- microseconds?How does the amplitude of the input waveform compare with the

amplitude of the output waveform- Larger/ smaller/the same?

Ans: ------------------.

4. Set the potentiometer fully clockwise and measure the output

with oscilloscope. Draw two cycles if the output waveform in

Figure E6-2C. How much resistance is now in series with the

capacitor? ---------- Ohms.Compute the RC time constant and record you

answer------------------microseconds.

Compare the shape of the output waveform, first with the input

waveform, and then with the output waveform you drew in step 3.

Output-to-input- Different/ Same: - Ans------------------------------.

Output to E6-2B: Different/ Same: - Ans------------------------------.

5. Replace the 0.0022 microfarad capacitor with a 0.1 microfarad

capacitor. Set the potentiometer fully clockwise. Draw two cycles

of the output waveform in Figure E6-2D.

The RC time circuit is; ------------------ microseconds.

Which is longer, one time constant or the positive portion of the

input waveform?

-----------------------.

6. Set the potentiometer fully clockwise. Use the oscilloscope toview the output waveform, cycle of the output waveform in the

space provided in figure E6-2E.

Compare the rectangular waveform that you drew in figure E6-2.

The waveform is most the RC time constant is;

---------------------microseconds.

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7. Construct the circuit shown in figure E6-3. Turn on the circuit

and set the generator frequency 1000Hz.

Repeat step 2 through 6 for circuit shown in figure E6-4. Draw the

cycles of the output the space provided in Fig E6-4. Please note

that in step 5, replace the 0.0022 microfarad capacitor the 0.1

microfarad capacitor.

Conclusions:



51



Experiment – 6

Capacitive voltage division and filteringObjective:-

1. To investigate the properties of a capacitive voltage

divider.

2. To verify the operation and characteristics of low and

high pass RC filters.


2. Power Supply.


4. 0.001 microforad capacitor.5. 0.039 microforad capacitor.

6. 0.1 microforad capacitor.

7. 0.47 microforad capacitor.

8. 4.7k, 1/2 watt resistor.

9. 47k, 1/2 watt resistor.

Procedure:- 1. Wire the circuit shown in figure E5-1.

2. Using your AC voltmeter, measure the input voltage.Vin= ---------------VAC.

3. Using the values given in the figure compute the voltage

division ratio.

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4. Using the value of input voltage obtained in step 2, compute the

output voltage expected with the voltage division ratio computed in

step 3. Predicted V o= --------.

5. Using your AC voltmeter, measure the voltage across C2. This is

the output voltage of the voltage divider. MeasuredVo= ------------Volts.

How does your computed value compare with your measured

higher/lower/same-----------?

6. Construct the circuit shown in figure E5-2. Set the generator

range switch to the LOW position (Hz to 2 KHz) and adjust the

frequency dial to the 200Hz position.

The experimental circuit is an RC filter. The experimental filter

circuit is a; -----------pass filter.

7. Using the values of resistance and capacitance shown in figureE5-2 compute the cut-off frequency Fco= ---------------.

8. Using your AC voltmeter measure the output voltage of the

signal generator. Be sure the ground lead of your voltmeter is

connected to the GND output terminal. (Measure the voltage

53



applied to the circuit where the 4.7k ohm resistor connects to the

SINE output. Record this voltage Vs= ---------------------V.

9. Determine the output voltage of the circuit at the cut-off

frequency. Make this computation using input voltage you

measured in the previous step. Record the output voltage at the cut-off frequency.

Vo = ------------------------VAC.

10. Connect your AC voltmeter across the 0.039 uf capacitor .Then

slowly vary the frequency dial on the generator in the clockwise

direction until the voltmeter reads the value of the voltage you

computed for the cut-off frequency. When this voltage is reached,

stop turning the knob and note the approximate frequency setting

of the dial. The generator frequency dial is only roughly calibrated, but you can estimate the frequency within several hundred cycles.

Record your estimate Fco= -----------Hz.

11. Construct the circuit shown in Figure E5-3 statement below.

The RC network shown is a; ----------------- pass filter.

12. Compute the cut-off frequency of the circuit in step 11, using

the component value given. Record your answer;

Fco= --------KHz.

54



13. Be sure that the generator range switch is in the LOW position

(200Hz to 2KHz). Turn the frequency dial to 200Hz. Connect your

AC voltmeter across the 47k ohm resistor. Measure the output

voltage of the circuit as you decrease the frequency. At this time

the output voltage from the circuit is. Increasing/decreasing-----------------------.

14. With the range switch on the generator in the HIGH position,

rotate the frequency dial to the maximum clockwise position (20

KHz). With your AC voltmeter, measure the input voltage to the

circuit, in other word, measure the voltage coming directly out of

the generator between the SINE and GND terminals.

Vs= ------------------------VAC.

15. Using the voltage you measured in the previous step as a

reference, compute the output voltage of this filter at the cut-off

frequency. Vo at cut-off= --------VAC.

16. Connect your AC Volt meter to the output of the circuit (across

the 47k ohm resistor). Rotate the frequency dial counter clockwise

until the voltmeter reads the voltage you connected for the cut off

frequency. When this voltage has been reached, note the dial

setting. The dial will give you only an approximation of the cut-off

frequency. Fco = --------------------Hz

Conclusions:



55



Experiment – 7

LC filtersObjective:-

1. To investigate the frequency response of band-pass filters.

2. To investigate the frequency response of band-stop filters.

3. To investigate the frequency response of high-pass filters.

4. To investigate the frequency response of low-pass filters.


2. Power Supply.


4. Frequency generator .5. 107mH choke.

6. 1-01 microforad capacitor.

7. 2-4700ohm ½ watt resistors (yellow, violet, red).

8. 1-1000ohm, ½ watt resistors (brown, black, red).

9. 1-10k ohm ½ watt resistor (brown, black, orange).

Procedure:- 1. Construct the circuit shown in figure E10-1.

2. Set the generator range switch to the high position (2 KHz to 20

KHz).

56



3. Refer to Figure E10-2. This diagram shows a typical response

curve for the circuit you built in step1. The curve was constructed

by measuring and plotting the response of several frequencies.

4. Connect your voltmeter across R. Set the generator frequency

control fully counter clockwise.Measure the voltage across R, V out = -----------VAC.

5. Rotate the frequency control clockwise to halfway between the

left most mark on the dial and the point labeled 2 KHz. The voltage

across the resistor is;

Vout = -----------------VAC.

6. Continue to turn frequency control clockwise. Measure Vout at

each of the marked points on the frequency dial and at several points in between. Try to measure at least 15 different points across

the frequency range. Record these voltages on a spate piece of

paper in order of increasing frequency.

7. Return to Figure E10-2 Establish a scale for Vout bon the left

hand side of the graph, ensuring your maximum and minimum

voltages can be plotted. Plot all of your voltage measurements,

including those voltages in step 4 and 5, on the graph.

8. Construct the circuit shown in Fig E10-11.

57



9. Connect the voltmeter across R. Using the above procedure plot

the response curve for this circuit. Use the graph in Fig E10-12 to

plot the curve.

10. Examine the circuit and its response curve. Determine the type

of filter that the capacitor and coil form.--------------------------filter.

11. Examine the circuit and its response curve. Determine the type

of filter that the capacitor and --------------------------filter.

12. Construct the circuit shown in Fig E10-7.

13. Connect the Voltmeter across R2 (not R1). Using the above

procedure, plot the response curve for this circuit. Use the graph in

Figure E10-8 to plot the curve.

14. Examine the circuit and its response curve. Determine the typeof filter that the capacitor and coil form.


16. Connect the voltmeter across R. Using the above procedure

plot the response curve for this circuit. Use the graph in Figure

E10-10 to plot the curve.

Conclusions:



58

final circuit manual

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