laboratory module electric circuit

Laboratory Module

Electric Circuit

High Voltage and Electrical Measurement Laboratory

Department of Electrical Engineering

Faculty of Engineering Universitas Indonesia

Electric Circuit Lab Module

High Voltage and Electrical Measurement Laboratory Department of Electrical Engineering, Faculty of Engineering UI

1

MODULE I

LABORATORY BRIEFING

The laboratory briefing will be informed later. All laboratory participant are required to

attend this briefing because it will be included in the scoring system.



2

MODULE II

BASIC OF ELECTRICITY AND MESH ANALYSIS

I. OBJECTIVE

1. To know the definition of electricity, current and voltage

2. To use the analysis of mesh in an electrical circuit

3. To understand the usage of super mesh analysis

4. To simplify the solution of voltage and current equation of an electrical circuit

II. BASIC THEORY

1. Basic of Electricity

Electricity is a form of energy that is resulted from the displacement of electrical

charge. Discussing about the basic of electricity, there is a close relation between voltage,

current, and resistance.

Voltage (V) is defined as the change of work that is needed to transfer a charge of

1 C which can be formulated into an equation

𝑽 = 𝒅𝑾

𝒅𝑸(𝑽𝒐𝒍𝒕)

Current (I) is defined as the amount of charge that flows per unit of time which can

be formulated into an equation

𝑰 = 𝒅𝑸

𝒅𝒕(𝑨𝒎𝒑𝒆𝒓𝒆)

Current requires the existence of voltage source, load, and a conducting wire to flow

(closed loop).

Resistance is a parameter measurement of the element to limit the flow of

electricity. Electrical resistance can also be defined as a collision between free electrons

(that flows in the conductor) with fixed charges that are in the material’s atomic bond.



3

The magnitude of resistance depends on density, length, and material’s cross-sectional

area.

Resistance can be formulated into an equation

𝑹 = 𝝆𝒍

𝑨(𝑶𝒉𝒎)

2. Electrical Element

Electrical element can be divided into two types based on their activeness, which

are active element and passive element.

Active element has some characteristics which can supply power, control

current/voltage on a circuit, as well as having gain function, for instances batteries,

diodes, and transistors.

Passive element has some characteristics which can only absorb power, cannot

control current/voltage, as well as having no gain function. The examples are resistor,

inductor, and capacitor.

Power sources can be divided into two types, which are independent sources and

dependent sources.

a. Independent Sources: a source whose magnitude and characteristics are not affected

by other elements.

b. Dependent Sources: a source whose magnitude and characteristics are affected by

other elements.

Dependent sources are divided into four types, which are:

1. Voltage-Controlled Voltage Source (VCVS)

2. Voltage-Controlled Current Source (VCCS)

3. Current-Controlled Current Source (CCCS)

4. Current-Controlled Voltage Source (CCVS)

3. Fundamental Laws

a. Ohm’s Law

“The amount of electrical current (I) that flows through a wire or conductor will be

proportional to the potential difference/voltage (V) that is applied to it and inversely

proportional with its resistance (R)”



4

Or it can be said that the voltage in a resistor is proportional to the current toward

that resistor.

Ohm’s law can be formulated into an equation

V = I. R

with V as the voltage, I as the flowing current and R as the resistance in a circuit.

b. Kirchoff’s First Law (Kirchoff’s Current Law, KCL)

“Amount of current that goes into a node is equal to the amount of current that goes

out of that node”

Kirchoff’s First Law is formulated into an equation

𝚺𝑰𝒊𝒏 = 𝚺𝑰𝒐𝒖𝒕

c. Kirchoff’s Second Law (Kirchoff’s Voltage Law, KVL)

“ In a closed circuit, the algebraic sum of electromotive force (E) and the sum of

potential drop is equal to zero ”

Kirchoff’s Second Law is formulated into an equation

𝚺𝑽 = 𝟎

4. Mesh Analysis

On mesh analysis, some factors need to be considered:

1. Circuit has to be on the same plane

2. Active element used is a voltage source

3. Passive element used is an impedance

4. Using Ohm’s law and Kirchoff II

5. Determining the current for each closed circuit

6. Creating voltage equation



5

How to acquire Mesh equation:

1. Decide the value of each element and source

2. Create the clockwise Mesh current on each Mesh

3. If the circuit only contains voltage source, use Kirchoff voltage law around each Mesh

4. If the circuit only contains current source, temporarily change circuit given by

substituting each source of its type with an open circuit. By using the Mesh currents,

use Kirchoff’s Second Law around each Mesh or super Mesh in this circuit.

III. EXPERIMENT TOOLS

1. DC Voltage Source = 1 piece

2. DC Voltmeter = 3 pieces

3. DC Amperemeter = 2 pieces

4. Load = 5 pieces

5. Cables

IV. EXPERIMENT CIRCUIT

Picture 1

V. EXPERIMENT PROCEDURE

1. Arrange the experiment circuit based on picture 1!

2. Record the voltage V1, V2, V3 and current A1, A2 for each change in the voltage source

value that matches with the experiment table



6

VI. QUESTIONS AND ASSIGNENTS

1. Calculate the value of I1 and I2 with Mesh analysis for each change in the voltage source

(V1)!

2. Find the measurement error for each change in value of voltage source (V1) and calculate

the average error.

3. Draw chart V1 against V2, V3, A1, A2 and write down the equation that states their

relation.



7

MODULE III

LINEARITY AND NODAL ANALYSIS

I. OBJECTIVE

1. To investigate a linear circuit.

2. To use the Nodal analysis in an electrical circuit

3. To understand the use of super node

4. To simplify the solution of current and voltage equations of an electrical circuit

II. BASIC THEORY

1. Linearity

A function or mathematical equation can be considered as linear when two

quantities are proportional to one another. There are two ways to prove a linear

equation/function: additivity and homogeneity.

Additivity : f(x + y) = f(x) + f(y).

Homogeneity : f(αx) = αf(x) for every α.

Linear circuit can be formed from independent sources, dependent sources and

linear elements. The magnitude of voltage given to a linear circuit will be proportional to

the magnitude of current that flows in the circuit.

Examples of linear elements are resistors, inductors, and capacitors. While, the

examples of non-linear elements are BJT, Diode, and Transistors.

2. Nodal Analysis

On Nodal analysis, a few things need to be considered:

1. Active element used is current source

2. Passive element used is admittance

3. Using Ohm’s law and Kirchoff I

4. Determining node voltage

5. Creating current equation



8

How to acquire nodal equation:

1. Show values for all elements and sources. Every current source has reference value.

2. Choose one of the nodes as reference. Write down the node voltage on every node that

was measured toward the reference.

3. If there is only current source existing, use Kirchoff First Law on every non reference

node.

4. If the circuit contains voltage source, temporarily change the given circuit by

substituting every source of that type with a short circuit. By using node voltage to

determined reference, use Kirchoff I on every node or current super node in the

changed circuit.


a. DC Voltage Source = 1 piece

b. DC Voltmeter = 3 pieces

c. DC Amperemeter = 3 pieces

d. Load = 5 pieces

e. Cables


Picture 1


1. Arrange the experiment circuit based on picture 1!

2. The controlled value is the current that flows out of the DC power supply, so that value

V0 is controlled by changing the voltage on DC power supply



9

3. Record the voltage V1, V2, V3 and current A1, A2 for each change in the value of current

source (A0) that matches with the experiment table

VI. QUESTIONS AND ASSIGNMENTS

Linearity

1. Create chart V (t) vs I (t) based on the experiment on millimeter block!

Nodal Analysis

1. Calculate the value of V1, V2, and V3 with nodal analysis for every current source

change.

2. Find the measurement error for every change in the value of current source and calculate

its average error.

3. Draw the chart of current source magnitude against V1, V2, V3, A1, and A2 and write

down the equation that states their connection.



10

MODULE IV

SUPERPOSITION ANALYSIS AND THEVENIN

I. OBJECTIVE

1. To determine the voltage on a linear circuit when there is more than one voltage source

2. To understand the usage of Thevenin theorem

3. To prove the Thevenin theorem on an electrical circuit

4. To simplify the solution of the voltage and current equation of a circuit

II. BASIC THEORY

In terms of electrical, electrical components can be categorized into linear and non-

linear. The examples of linear components are resistor, inductor, and capacitor, while

examples of non-linear components are transistor and diode.

In a linear circuit, there are a few theorems that can be used to simplify the analysis

and circuit calculation:

1. Superposition

In every linear networks that contains a few sources, voltage or current that flows

through every load or source can be calculated by performing algebraic sum of every

voltage or current that is produced by each independent source that operates alone, with

every independent voltage source changed with short circuit and every other current

source changed by open circuit.

2. Thevenin Theorem

NA NB

i(t)

Picture 1

NA : Circuit that contains passive and active elements



11

NB : Circuit that contains only passive elements

From NA to NB flows current i(t)

1. Place voltage source V(t) that has a value which such a way that current doesn’t flow

from NA to NB

NA NB

V(t)+ - 1

1'

Picture 2

.

2. i(t) = 0 means NA and Nb can be terminated on terminal 1 – 1’

3. Voltage equation on 1 – 1’ in an open circuit state:

4. -V1-1’ + V(t) = 0; V(t) = V1-1’

5. V1-1’ is the circuit voltage in open circuit state (V open circuit)

6. Calculate the V(t) = V1-1’

7. Reverse the polarity V(t) and erase voltage/current source on NA

8. So, the current i(t) flowing from NA to NB is the same as before



b. DC Voltmeter = 1 piece

c. DC Amperemeter = 1 piece

d. Load = 4 pieces

e. Cables



12


Thevenin Theorem

Picture 1


1. Create the circuit based on picture 1

2. Turn on the power supply and do a warm up for a few moments and adjust the position

of voltage source

3. Insert S1&S3 to the position 1 and then insert S4. Record Va and load current IL close

loop. Repeat this step for different voltages

4. Return the magnitude of power supply to the position 0

5. Open S4 and then place the voltmeter with pole (+) on the tip of the Thevenin circuit and

pole (-) on reference (Voc in the picture). Record Voc with Vs same as step 3.

6. Return the magnitude of power supply to the position 0

7. Move S1&S3 to position 2 and insert S2. After that, move the position of voltmeter with

pole (+) to the tip of the load and pole (-) to the tip of the Thevenin circuit (VTH in

picture).


1. Does load current IL on V.1.3 and V.1.7 have the same magnitude? Please explain!

2. By not changing the experiment circuit, can IL on V.1.7 be made to 2 x IL on V.1.3?

Explain!



13

3. Compare measurement results of Voc toward the actual calculation result! Please

calculate!



14

MODULE V

NORTON ANALYSIS

I. OBJECTIVE

1. To understand the usage of Norton Theorem

2. To prove the Norton Theorem on an electrical circuit

3. To simplify the solution of the voltage and current equation from an electrical circuit

II. BASIC THEORY

Norton Theorem

1. Place the current source based on picture 1 that has a value so that i(t) is the same as ig

and there is no current flow to NB

NA NBigi(t)

1

1'

Picture 1

2. This means i(t) = ig. Short circuit at terminal 1-1’. NA and NB released at 1-1’.

NA NBi(t)

1

1'

Picture 2

3. Calculate the short circuit current ig

4. Reverse the polarity of ig and erase all active elements on NA

5. Thus, the current i(t) flowing from NA to NB is the same as before



15

igNA NBi(t)

1

1'

Picture 3



b. DC Voltmeter = 1 piece

c. DC Amperemeter = 1 piece

d. Load = 4 pieces

e. Cables


Picture 4


1. Arrange the circuit based on picture 4

2. Turn on the power source and adjust the position of voltage source

3. Insert S1 to position1. Record Vs and load current IL (A2) close loop. Repeat this step

for different voltages.

4. Insert S3. Record the short circuit current Isc (a1) with Vs from step 3



16

5. Return the power source to position 0. Close S1, open S3 and move S1 to position 2.

Adjust the power source at the position of the current source. Exchange the polarity of

amperemeter A1 and record the load current IL (A2) for the same current (A1) based on

step 4.


1. Does load current IL on V.2.3 and V.2.5 have the same magnitude? Please explain!

2. Is load current IL on Norton and Thevenin experiment the same for the same vs value?

Why?

3. Compare the measurement result Isc with calculation result! Calculate the 5 errors!

4. Find RTH from experiment result and compare with RTH from actual calculation result!

Calculate % error!

5. Create chart Voc vs Isc with the same Vs!



17

MODULE VI

TWO PORTS CIRCUIT

I. OBJECTIVE

1. To determine the admittance and impedance parameter of a two ports circuit

2. To determine the circuit parameter for simplifying and systematizing the network analysis

with two linear layover points

II. BASIC THEORY

Two ports circuit is a circuit that has a pair of terminals on the input and output side.

Two ports circuit is used frequently on communication system network, control system,

power system, and electronic circuit. Two ports circuit is illustrated as follows:

+

--

Ia

IcIb Id

V1 V2

+

Picture 1

A = Terminal C = Positive pole` E = Blackbox

B = Negative pole D = Port

Requirement of a two ports circuit is where the circuit must be to be reciprocal and

symmetrical. A circuit is called reciprocal whenever the voltage measured on port 2 against

current on port 1 is equal to voltage measure on port 1 against port. The other requirement

is where there is no dependent source on a reciprocal circuit. While a circuit is said to be

symmetrical if input impedance is equal to output impedance.

Symmetrical Reciprocal Port Condition

𝑉1

𝐼1=

𝑉2

𝐼2

𝑉1

𝐼2=

𝑉2

𝐼1 ∑ 𝐼𝑖𝑛 = ∑ 𝐼𝑜𝑢𝑡

A

B

D

C

E

𝐼1

𝐼1

𝐼2

𝐼2



18

Analysis of a two ports circuit is based on the relationship between the current and

voltage on a network terminal to get the network parameter.

Two ports parameter can be categorized as:

a. Admittance Parameter (Y)

b. Impedance Parameter (Z)

c. Hybrid Parameter (h)

d. Transmission Parameter (abcd)

e. Inverse Transmission Parameter

f. Inverse-hybrid Parameter (g)

Admittance parameter can be obtained by writing the current equation as a function of

the network voltage.

1 11 1 12 2

2 21 1 22 2

1 11 12 1

2 21 22 2

Y

Y Y

I Y V Y V

I Y V Y V

I Y V

I V

= +

= +

=

Impedance parameter can be obtained by writing the terminal voltage equation as a

function of the network current.

1 11 1 12 2

2 21 1 22 2

1 11 12 1

2 21 22 2

Z

Z Z

V Z I Z I

V Z I Z I

V Z I

V I

= +

= +

=

Relationship between two ports circuit is called interconnection. There are 3 types of

interconnection on two port circuits which are:



19

1. Series Connected Interconnection

2. Parallel Connected Interconnection

3. Cascade Connected Interconnection


a. 1 Power Source

b. 2 Amperemeter DC

c. 2 Voltmeter DC

d. Loads

e. Cables



20


1. Admittance Parameter

2. Impedance Parameter

Picture 3

B

I1 I2

V2

+

V1

R1 R2

R3

-

+

-

A1

V

P Q

R

A2

A

S

+ -

+ -

- +

V2

+

V1

I1 I2

R1

R2

R3

-

+

-

V

A

V

A - + + -

Picture 2



21


A. Admittance Parameter

1. Arrange the circuit based on picture 4.2

2. Connect point B with R and point S with P

3. Give the power source to V1 and reverse the polarity of A2.

4. Turn on the power supply. Record the current I1 and I2 for every voltage increase of

V1

5. Return the power source to position zero (0). Turn off the power supply

6. Connect point A with R and S with Q

7. Give the power source to V2 and reverse the polarity of A1 and A2

8. Turn on the power supply. Record the current I1 and I2 for every voltage increase of

V2

9. Return the power supply to position zero (0) and turn off the power supply

B. Impedance Parameter

1. Arrange the circuit based on Picture 4.3!

2. Give the power source to V1

3. Turn on the power supply. Record the voltage V1 and V2 for every increase of I1

4. Return the power source to position zero (0) and turn off the power supply

5. Give the power source to V2

6. Turn on the power supply. Record the value of current V1 and V2 for every increase

of I2

7. Return the power source to position zero (0) and turn off power supply


1. Explain what is meant by two ports circuit?

2. Explain the reason a two ports circuit is needed in an electric circuit analysis?

3. Create the hybrid matrix, inverse hybrid, transmission and inverse transmission from the

experiment circuit!



22

MODULE VII

AC CIRCUIT

I. OBJECTIVE

1. To analyze the difference between AC and DC

2. To analyze the AC circuit

3. To analyze the properties of active and passive elements on an AC circuit

4. To solve the current and voltage equation of an electrical circuit using AC source

5. To be able to apply the laplace equation for solving a simple electrical circuit equation

II. BASIC THEORY

1. Alternating Current (AC)

Alternating current in general is back and forth current. Scientifically, the meaning

of AC is an alternating current in terms of polarity and its magnitude over time. Generally,

AC chart is illustrated in the form of a sinusoidal chart:

The following factors are what differentiates between AC and DC:

• Polarity

• Frequency

• Power

• Power Factor

• Generation

• Property of L and C element



23

2. Inductor

An inductor or reactor is a passive element (mostly torus shaped) that can store

energy in magnetic field that is induced by the electrical current passing through it. The

ability of the inductor to store energy is determined by its inductance, in unit Henry. An

inductor is usually a conducting wire that is formed into coil. The coil helps to make a

strong magnetic field inside the coil due to the Faraday’s law of induction.

3. Capacitor

Capacitor is an electrical component commonly, in physical terms, made from two

conductors that are separated by an isolating material or dielectric. Capacitance is a

measurement of the capacitor’s ability to store energy in electric field. Capacitance is

expressed in Farad. 1 Farad describes the capacitor’s ability to store 1 coulomb of electric

charge whenever 1 volt of voltage is applied.

4. Power on AC circuit

• Active Power (P)

Is the power used to produce actual energy used

• Reactive Power (Q)

Is the power that appears due to the presence of inductive and capacitive components

• Apparent Power (S)

Is the power that is generated and transmitted by the power plants and it is the result

of multiplication between rms voltage and rms current in a network.

5. Laplace Transform

Laplace transform is a technique used to simplify the problem in a system that has

an input and output by doing transformation from one domain to another. This method is

used in analyzing the AC circuit to solve current and voltage equation.



24


a. AC Power Supply = 1 piece

b. Variable Capacitor = 1 piece

c. Variable Inductor = 1 piece

d. Variable Resistor = 1 piece

e. AC Voltmeter = 2 pieces

f. Cables



1. Arrange the experiment circuit based on the picture of the experiment circuit

2. Record the voltage value measured on Voltmeter

3. Repeat step 2 with different inductance and capacitance values


1. What will happen if the capacitor and inductor are used with DC source? Explain!

2. Find the value of circuit time function by using second order equation!



25

MODULE VIII

THREE PHASE CIRCUIT

I. OBJECTIVE

1. To understand the definition of phase and polyphase.

2. To know the three phase system configuration: wye connection and delta connection.

3. To express the connections needed in three phase load circuit.

4. To differentiate the symmetrical load and asymmetrical load.

5. To determine the current on phase channel for asymmetrical load.

6. To know the wye-delta conversion.

II. BASIC THEORY

Phase represents a change in voltage or current versus time represented in the form of

an angle. In an electrical system, it is commonly used for three phase circuit on the

transmission and distribution of power. Three phase circuits are chosen by considering the

economic aspect and the optimization of the electrical system. In the generation of three

phase circuit, it requires a three-phase AC generator. Here is a picture of a three-phase AC

generator:

Picture 1

Three phase circuit has two configurations, the star circuit and delta circuit.



26

A. Delta Connection In the delta circuit, the three impedances of the load are connected in series with

each other. The three phase line are each connected by a node between the two loads.

Picture 2

If all three phase loads of the three phase are identical, this is called symmetrical

load. If the three loads are different, it is called asymmetric loads.

In delta connection, line voltage and phase voltage have the same value, then Vline

= Vphase. But the line currents and phase currents are not equal, and the relationship

between the two currents can be obtained by using Kirchoff's law, so Iline = √3 Iphase.

B. Wye Connection In a star load circuit, the end of the three loads from each phase are connected to a

single node where the neutral wire is connected. Tthe other end of the three loads of each

phase is connected with line which is the in/out line current (A, B, & C).

Picture 3



27

If the load value of each phase of the three phase is identic (same value and angle),

therefore this is called as symmetrical load. If the values are different, it is called

asymmetrical load.

On a Wye connection, line current and phase current have the same value, therefore

Iline = Iphase. But line voltage and phase voltage are not the same because Vline = √3

Vphase.

C. Delta-Wye Conversion A delta circuit can be converted to a wye (star) circuit and vice versa. The

conversion method is using the formula below.

Picture 4


a. 1 set 3 Phase Power Supply

b. 1 set Transformer Circuit

c. 4 pieces Amperemeter

d. 1 piece Multimeter

e. 3 pieces Variable Resistor

f. 1 set Connector Cable



28

IV. EXPERIMENT CIRCUIT DIAGRAM

Delta Connection

Picture 5

Wye Connection

Picture 6


VOLTAGE AND CURRENT MEASUREMENT ON DELTA CONNECTION Experiment 1

1. Arrange the delta connection experiment circuit (picture 5) with R1 = R2 = R3 = 220 ohm

(symmetrical).

2. Measure the line current IL on the three phase line and phase current Iph on three phase

resistors using an amperemeter.

3. Measure the line and phase voltage by using a multimeter.

4. Compare the line current and phase current.

Experiment 2

1. Arrange the asymmetrical experiment circuit by replacing the value of R3 to 110 ohm.

2. Measure the phase current and line current.

3. Measure the phase voltage and line voltage.



29

4. Compare the line current with phase current.

VOLTAGE AND CURRENT MEASUREMENT ON STAR CONNECTION Experiment 1

1. Arrange the wye connection circuit (Picture 6), with R1 = R2 = R3 = 220 ohm

(symmetrical).

2. By using the amperemeter, calculate the line current Il and phase current Iph, and also

neutral current In.

3. With multimeter, calculate the phase voltage Vphase and line voltage Vline (voltage

between phases).

4. Compare the line voltage and phase voltage.

Experiment 2

1. Arrange the asymmetrical experiment circuit by replacing the value of load R3 to 100

ohm.

2. Calculate the current on each phase, neutral current, phase voltage and voltage between

phases.


A. Delta Connection 1. Write the relationship between line current and phase current and between line

voltage and phase voltage in a symmetrical delta connection!

2. What happens if one of the phases is removed from the delta connected circuit?

3. What happens if two phases are removed on a delta connected circuit?

4. What happens if one of the lines is removed on a delta connected circuit?

B. Star Connection 1. Write the relationship between line current and phase current and between line

voltage and phase voltage in a symmetrical star circuit!

2. What happens if the neutral line wire on an asymmetrical star circuit is removed

from the circuit?

3. Draw the phase voltage vector diagram when the neutral wire is removed from the

circuit!



30

MODULE IX

POST TEST

Post test is the final test regarding the material that has been tested in Electric Circuit

Laboratory. All participants are obligated to join the post test because this is the part of scoring

component. Time and place of the post test will be informed later.



31

REFERENCE

- Johnson, David E. Electric Circuit Analysis.1997. Prentice Hall

- Ramdhani, Mohammad. RANGKAIAN LISTRIK. 2008. Penerbit Erlangga

- and the other reference book

laboratory module electric circuit

Documents