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Preface

Praise the Almighty God for all of His blessings in making the

completion of this student laboratory module possible. We would also like

to express our sincere thanks for the help from those who contributed in

providing the material content of this practicum properly.

We all hope that this laboratory module could increase the

knowledge and the experience of the readers and/or the practitioners of

Electronics Circuit laboratory Universitas Indonesia. Hopefully, in the

future, we could fix as well as improve the contents of this laboratory

module in order to be better.

Due to our limited knowledge and experience, we believe that there

is still a lot of deficiencies in this laboratory module. Therefore, we really

welcome any suggestions and criticisms from the readers and/or the

practitioners of Electronics Circuit laboratory Universitas Indonesia for

the perfection of this paper.

Depok, February 15th, 2017

Author

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Table of Contents

Cover ...................................................................................... i

Preface ................................................................................... ii

Table of Contents ................................................................... iii

Lab Management Structure ................................................... viii

Lab Rules and Regulations .................................................... x

Marking System ..................................................................... xii

Individual Module Marking ................................................... xiii

Module I – Introduction ......................................... 1

1. Practicum Objectives................................................... 1

2. Basic Theory Bullet Points .......................................... 1

3. Basic Theory ................................................................ 1

a. Equipments used in Electronics Circuit

Laboratory

i. Breadboard ............................................... 2

ii. Power Supply ............................................ 3

iii. Multimeter................................................ 4

iv. LCR Meter ................................................ 4

v. Oscilloscope .............................................. 5

vi. Function Generator .................................. 6

b. Components used in Electronics Circuit

Laboratory

i. Resistor ..................................................... 6

ii. Capacitor .................................................. 7

c. Introduction to Electronics Device

i. Structures of Atom ................................... 8

ii. Characteristics of Atom ............................ 10

iii. Mobility of Electron and Hole .................. 11

iv

iv. Atom Conductivity .................................... 12

v. Semiconductor Material ........................... 13

vi. Intrinsic and Extrinsic

Semiconductor ......................................... 14

vii. Carriers and Semicondcutor Types .......... 14

viii. PN Junction Diode ................................... 15

ix. Bias Mode and PN Junction Diode

Characteristics .......................................... 17

d. Practicum ........................................................... 19

e. Reference ........................................................... 19

Module II – Diode ................................................... 20



3. Basic Theory ................................................................ 20

a. Type and Functions of Diode ............................. 20

b. Equivalent Circuit of Diode ............................... 21

c. Applications of Diode

i. Half Wave Rectifier Circuit ...................... 22

ii. Full Wave Rectifier Circuit ....................... 23

iii. Clippers Circuit ......................................... 24

iv. Clampers Circuit ....................................... 25

v. Voltage Regulator Circuit ......................... 26

4. Practicum .................................................................... 27

5. References ................................................................... 32

Module III – Bipolar Junction Transistor (BJT) ..... 33



3. Basic Theory ................................................................ 33

a. Introduction ....................................................... 33

b. BJT Working Principle ...................................... 34

c. BJT Configuration ............................................. 35

i. Common Base ........................................... 35

ii. Common Emitter ...................................... 36

iii. Common Collector .................................... 37

d. BJT AC Analysis ................................................. 39

i. BJT Transistor Modelling......................... 39

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ii. Model Transistor Re ................................. 40

iii. Fixed Bias Common Emitter .................... 43

iv. Voltage Divider Bias CE ........................... 46

e. Practicum ........................................................... 48

f. BJT BC 107 Data Sheet ...................................... 52

g. References .......................................................... 54

Module IV – Field Effect Transistor (FET) .............. 53



3. Basic Theory ................................................................ 55

a. Definition ........................................................... 55

b. FET and BJT Difference .................................... 56

c. Types of FET ...................................................... 55

i. JFET ......................................................... 56

ii. D-MOSFET ............................................... 61

iii. E-MOSFET ............................................... 63

d. AC FET Equivalent Circuit ................................. 66

4. Practicum .................................................................... 67

Module V – Frequency Response of BJT ................. 69



3. Basic Theory ................................................................ 69

a. Decibel ............................................................... 69

b. Bode Diagram .................................................... 70

c. Frequency Response .......................................... 71

d. Frequency Response of BJT Voltage Divider

Cicrcuit ............................................................... 71

4. Practicum .................................................................... 74

5. Reference..................................................................... 76

Module VI – Frequency Response of FET ............... 77



3. Basic Theory ............................................................... 77

a. Decibel ............................................................... 77

b. Bode Diagram .................................................... 78

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c. Frequency Response .......................................... 79

d. Low Frequency Response of FET Amplifier

........................................................................... 80

High Frequency Response of FET Amplifier

........................................................................... 81

4. Practicum .................................................................... 83

5. References ................................................................... 84

Module VII – Operational Amplifier ....................... 85



3. Basic Theory ................................................................ 85

a. Introduction ....................................................... 85

b. Ideal Op-Amp .................................................... 87

c. Inverting Amplifier ............................................ 88

d. Non-inverting Amplifier .................................... 89

e. Integrator Circuit ............................................... 91

f. Differentiator Circuit ......................................... 91

g. Op-Amp Data Sheet ........................................... 93

4. Practicum .................................................................... 94

5. References ................................................................... 98

Module VIII – Active Filter ..................................... 99



3. Basic Theory ................................................................ 99

a. Introduction ....................................................... 99

b. Sallen-Key Formula Derivation ......................... 103

c. Gain Block Diagram ........................................... 104

d. Ideal Transfer Function ..................................... 105

e. High Pass Filter Transfer Function and

Cutoff Frequency ............................................... 105

f. Low Pass Filter Transfer Function and

Cutoff Frequency ............................................... 106

4. Practicum .................................................................... 106

5. References ................................................................... 111

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Module IX – Application ......................................... 112



3. Basic Theory ................................................................ 113

a. Light Sensor as Automatic Switch for 220V Lamp

................................................................................. 111

b. Astable Multivibrator with Discrete Component

................................................................................. 114

c. Astable Multivibrator with IC (Integrator Circuit)

LM555 ...................................................................... 118

d. Motor Driver with Optocoupler ............................... 121

4. References ......................................................................... 125

Modul X – Final Project .......................................... 126

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Laboratory Management Structure

1. Head of Universitas Indonesia Electronics Laboratory

Dr. Ir. Agus Santoso Tamsir, M.T.

2. Universitas Indonesia Electronics Laboratory Assistants

Alfiqie Tanjung (2013)

Arif Widianto (2013)

Heinz Kristian Pramono (2013)

Josef Stevanus Matondang (2013)

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Faisal Abdillah (2014)

Istighfari Dzikri (2014)

Kresna Devara (2014)

Michael Hariadi (2014)

Savira Ramadhanty (2014)

Yosua Adriadi (2014)

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Lab Rules and Regulations

1. Students are obliged to follow the entire sequence of Electronics Circuit Practicum

that consists of 5 (five) Practicum Modules.

2. Students are obliged to read the General Safety Guidelines and the General Safety

of each practicum module as to avoid unwanted things from occuring.

3. It is mandatory that each student dress modestly by wearing a collared shirt as

well as shoes during the course of the practicum.

4. Students are required to prepare all of the practicum materials from the

laboratory module, the materials learned in class, and other sources that are

relevant.

5. Students should bring the identity card of the practicum, the preliminary task, and

Basic Theory that are all collected by the respective lab assistant before the

practicum starts. The preliminary task will be given no later than 24 hours before

each shift begins.

6. Each student must bring the Basic Theory written on A4 paper using the given

format when going for the practicum, and that will be the supporting material

when starting the practicum. The Basic Theory will be labeled/stamped by the lab

assistants.

7. Each student who is in the same shift should bring a Power Point file that will later

be presented to the laboratory assistants at the beginning of the practicum

8. During the practicum, students are obliged to ask the lab assistants to check their

circuit/s before collecting data.

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9. Types of reason that are acceptable to be absent are being sick (must bring notes

from Doctor/Hospital), sudden disaster/tragedy, and force major (flood, heavy

earthquake, fire incident, etc).

10. Replacement of the practicum schedule due to valid reason are accepted, however,

new schedule must be decided along with the other group members.

11. Each student is obliged to fill the practicum attendance list and the practicum

report.

12. Tolerance for tardiness of each Practicum Module is 15 minutes. If the student is

late for more than 15 minutes without providing valid reasons, he/she could still

join the practicum of that module, but will get zero mark in the “borang”

form.

13. Students who want to change their practicum schedule could contact the

coordinator of the practicum. Schedule replacement is only permitted if the

students have valid reason/s that can be accepted by the assistant.

14. If the students do not join the practicum, their mark of that practicum module is

zero.

15. The result of the practicum is determined by the behavior and the activeness of

the students during the practicum, including the oral test before the practicum

starts. Behaviour that is prohibited include any actions which could interfere the

practicum itself such as making jokes, distracting other groups, leaving the lab

directly without tidying up the lab tools after the practicum, and lastly, playing

with gadgets.

16. Additional Tasks should be done in A4 paper and is put together on the lab report.

17. All absence permissions and complaints related to technical implementation of

the practicum module may be delivered to the coordinator of practicum, Savira

Ramadhanty (085746546788).

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Marking System

Each practicum module has weight percentage of:

Component Percentage

Basic Theory 10%

Preliminary Task 5%

Data Analysis 30%

Behavior, Practicum, Activeness, Oral test 40%

Additional Task 10%

Conclusion 5%

If a student does not enroll for 5 modules, he/she fails the practicum

(D/E).

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Marking Percentages of Each Module

Component Percentage

Module I Introduction 10 %

Module II Diode 10 %

Module III Bipolar Junction Transistor 10 %

Module IV Field Effect Transistor 10 %

Module V BJT Frequency Response 5 %

Module VI FET Frequency Response 5 %

Module VII Operational Amplifier 10 %

Module VIII Filter Circuit 10 %

Module IX Electronics Circuit Application 10 %

Module X Final Project 20 %

Total 100 %

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Module I

Introduction to Electronics Circuit Practicum (ECP)

1. Practicum Objectives

Know the tools that are used in ECP

Know the components that are used in ECP along with the

standards in reading and using them

Know and understand the basic theory of Electronics Device

2. Basic Theory Bullet Points

Equipments that are used in ECP

Components that are used in ECP

Basics of Electronics Device

3. Basic Theory

Equipments that are used in Electronics Circuit Practicum

Before the practicum begins, we all must know which equipments will

be used for the practicum, this time we will use the following equipments:

Breadboard

Power Supply

Multimeter

LCR Meter

Oscilloscope

Function generator

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1. Breadboard

Breadboard is an equipment that is used to create and test electronic

circuits in a quick manner (instantly), before the finalization of

circuit design is started. Breadboard has many holes that has a

function for placing components such as resistor or IC (Integrated

Circuit). Here is shown an example of a breadboard in general:

Figure 1.1 Breadboard

Breadboard is equipped with layer of metal strip that is placed

throughout the bottom of the board and connects the holes that are

on the top (surface) of the board. The layout of the metal strip is

shown below:

Figure 1.2 Metal strip Layout at the bottom of the Breadboard

The holes at the top and the bottom are connected horizontally,

however, the one in the lab has a separator/divider at the middle in

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which a jumper is needed to fully connect the horizontal path. As for

the holes placed in the middle, they are connected vertically and is

separated with the top and bottom holes as shown in figure 1.2.

2. Power Supply

The power supply gets the source of electricity from PLN with a

voltage value of 220V AC. There is transformer in the power supply

to reduce (step-down) the voltage. Aside from that, the power

supply is able to produce DC voltage, and there is fuse contained in

it to protect itself from being damaged due to the error in the

circuit.

Significant elements in a power supply consist of:

Power supply source

Vratings on power supply

Variable DC

Jumper

Source circuit +/-15 Volt

AC ground and DC ground

Figure 1.3 Power supply on protoboard

3. Multimeter

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Multimeter is used to measure voltage and current. There are

two types of Multimeter used, that is, the analog multimeter and the

digital multimeter. In general, the term multimeter refers to an

instrument that can be used as a voltmeter or an ammeter (ampere

meter). It is important to note that value which appears on the

multimeter is the RMS (root-mean-square) value. When measuring

voltage, the multimeter is connected in parallel. Whereas, when

measuring current, the multimeter is connected in series.

Figure 1.4 Multimeter on protoboard

4. LCR Meter

The LCR meter that is used in the lab is the digital LCR meter.

LCR meter can be used to measure the magnitude of inductance L

and capacitance C. There are 3 frequency measurements on the lab

LCR meter.

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Figure 1.5 Boonton 5100 LCR Meter

5. Oscilloscope

Oscilloscope is a laboratory instrument that is generally used for

describing and displaying graph of an electrical signal. The graph

below shows how signal changes with respect to time.

Figure 1.6 X, Y and Z components of the displayed waveform

The vertical axis (Y) represents voltage while the horizontal axis

(X) represents time. Intensity or brightness of the display of

oscilloscope is sometimes represents the Z axis. The voltage that

can be read from the oscilloscope is regarded as the peak-to-peak

voltage. For this Electonics Circuit Practicum, the oscilloscope used

is the analog one.

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Figure 1.7 Analog Oscilloscope

6. Function Generator

Function Generator obtains DC supply from the power supply.

Function Generator is able to produce signal with frequency range

up to 200 kHz. The types of wave that could be generated by the

power supply are sinusoidal, triangle, and square.

Significant elements in a function generator consist of:

Power source

Frequency Range

Wave types/forms

Grounding

Components that are used in Electronics Circuit Practicum

1. Resistor

Resistor is an electronic component whose function is to limit

the electrical current flow on an electronics circuit. Resistor could also

be used to give voltage that is specific for an active device, for instance,

a transistor. Symbol of resistor:

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The following shows how to read resistor bands:

Figure 1.8 Resistor bands reading

2. Capacitor

Capacitor is an electronic component whose function is to store

electrical charge. Capacitor is made of two conductors that are

separated by a material called dielectric. Capacitance due to a

capacitor is the amount of electrical charge stored in the capacitor

itself when it is given voltage that is as big as its source.

Capacitor is categorized into 2 groups, namely, polarized and

non-polarized. In general, capacitor with low capacitance value is

included in the non-polarized category.

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The following shows how to read capacitor:

Figure 1.9 Capacitor values reading

Introduction to Electronics Device

1. Structures of Atom

Everything that exists in nature, as we all know, is built by

elements in which elements are built by atoms. Atom is the smallest

possible matter in making up an object. When we were introduced to

atoms in high school, we acknowledged that there are sub-atomic

particles such as protons, electrons, and neutrons. Among said

particles, the only particle that is capable of moving is the electron.

That phenomenon leads to a possibility of an atom to lose or to gain an

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electron (or more). The atom which loses or gains an electron is called

ion. Ion that gains an electron is known as a negative ion, whereas, the

one which loses an electron is knwn as positive ion.

The structure of an atom can be described by the following

Bohr’s atomic model:

Figure 1.10 Atom structure: a. Silicon, b. Germanium,

c. Gallium and Arsenic

According to the above figure, the black dots are electrons and

the circular lines represent the energy levels in each atom. Electron is

a sub-atomic particle that is negatively charged. Electron constantly

moves and does not occupy the same energy level all the time.

Electrons can move between different energy levels. When an electron

leaves, it creates a hole. Hole is referred to as a positive charged sub-

atomic particle.

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2. Characteristics of Atom

Every matter can be described by using a band diagram

representation. Band diagram is an energy level representation of

atoms. Below is an example of a band diagram of a semiconductor

material:

Figure 1.11 Band Diagram

In figure 1.11, it is shown that a band diagram representation

consists of two major bands, namely, conduction band and valence

band. Those two bands are separated by an area known as the band

gap. Conduction band is an energy band where the electrons are able

to move freely. Whereas, valence band is an energy band where

electrons are found in static conditions, in other words, we can find

most of the electrons in valence band are in static conditions.

The separating area, band gap, is an area where electrons cannot

be found. This area represents the conductivity of an atom, and it

varies for each kinds of atoms. Band gap also represents the required

amount of energy to move an electron from the valence band to the

conduction band.

The amount of electrons found in valence band and holes found

in conduction band can be obtained by two factors. First, the density of

states of those particles in their respective bands should be known,

then the probability of states being filled by a particle for each levels is

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obtained. Density of states is the amount of electron states (that can be

filled by electrons) which is available in a certain energy level. From

the density of states, Fermi level of an atom (the energy level where

the probability of electrons/holes found is 50%) is obtained.

3. Mobility of Electron and Hole

The analogy commonly used to describe their mobility is a tube

filled with water. Water represents electrons and air represents holes.

No air will be left when the tube is completely filled with water and

when the tube is tilted, nothing moves. This also occurs when the tube

is empty. In both cases, no electrons and holes can move.

When the tube is filled half-full, with air filling the extra space,

and if the tube is tilted, it can be seen that the air also moves to

compensate the movement of water. In this case, electrons and holes

are able to move. This concludes that if a band is completely filled or

completely empty, no movement of electrons or holes shall occur.

Figure 1.12 Fluid Analogy

a. Completely filled and completely empty

b. Half filled

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4. Atom conductivity

As explained above, the conductivity of an atom is defined by the

band gap area in the band diagram. Wider band gap causes electron to

hardly move from valence band to conduction band, and vice versa.

Overlapping bands allow electrons to be able to move freely, this is a

characteristic of a conductor’s atoms.

Wide band gap prevents electron to move in between bands,

band gap distance correlates with the amount of energy needed to

move the electrons. We can see that there are no electrons at all in the

conduction band, and valence band is filled completely. Therefore, we

can conclude that this is a band gap of an insulator’s atoms (Eg > 3eV).

Band gap which distance between the bands are between the

distances of conducting materials’ atom and insulating materials’ atom

is one of the characteristics of a semiconductor’s atom. Semiconductor

material atoms can be controlled to be conducting or insulating

according to needs, the band gap varies around 2 electron volts (Eg <

2Ev).

Figure 1.13 Atom Conductivity Band Diagram

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5. Semicoductor Material

According to the illustration above, the elements that are

classified as semiconductor are Silicon (Si), Germanium (Ge), and also

a III-IV compound such as Galium Arsenide (GaAs). Silicon and

Germanium is called the elemental semiconductor, while Galium

Arsenide is a semiconductor that is formed by a covalent bond

between Galium and Arsenic.

Every semiconductor material has different band gap energies.

Acknowledge figure 5, although Germanium has a lower band gap

energy, it’s not used commonly in most electronics devices. The

availability of Germanium in nature is one of the reason it’s not

commonly used. GaAs has a bigger band gap, so in chip fabrication,

silicon is the mostly used. Besides its band gap, silicon can be found

abundantly in nature.

Figure 1.14 Semiconductor material band gap values

6. Intrinsic and Extrinsic Semiconductor

As explained before, the conductivity of a semiconductor can be

controlled precisely according to your needs. The conductivity is

controlled by adding the material with another atom. An intrinsic

semiconductor is a condition of a pure undoped semiconductor, while

extrinsic semiconductor is a semiconductor that has been doped by

another atom to change the electrical properties. The process of

adding another atom to a semiconductor material is called doping and

the atoms are called the dopants.

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There are two kinds of dopants, which are donors and acceptors.

Donor dopants have more valence electrons than the semiconductor

atoms, so that the doping process increases the amount of electrons in

the semiconductor materials. Donor dopants come from the group V of

the periodic table, such as Phosphorus or Sulphur and Arsenic.

Acceptor dopants have less valence electrons than the semiconductor

atoms, so that the doping process increases the amount of holes in the

semiconductor materials. Acceptor dopants come mostly from group

III of the periodic table, such as Boron, Galium, or Indium.

Applying dopants to intrinsic semiconductor causes a change in

Fermi level of the semiconductor material. If given some donor atoms,

the Fermi level will approach the conduction band, while given some

acceptor atoms, the Fermi level will move closer to the valence band.

7. Carriers and Semiconductor Types

Semiconductor that has been given an acceptor dopant is called

a p-type semiconductor, while a semiconductor material that has been

given a donor dopant is called an n-type semiconductor. Each type of

semiconductor has two kinds of carriers, namely, majority carriers and

minority carriers. Majority carriers represent the carrier that suits the

type of the semiconductor material. Majority carrier in a p-type

semiconductor is a hole, and the minority carrier is an electron, and

vice versa.

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8. PN Junction Diode

PN junction diode is considered as an electronic device

consisting of two types of semiconductor explained above that are

combined together.

Figure 1.15 P-Type & N-Type Semiconductor before and after contact

Figure above represents how two types of semiconductor are

combined together to become one entity. It can be observed that the

left figure before contact (System 1) is of N-Type while (System 2) is of

P-Type based on their Fermi level. On the contrary, the right figure

before contact does the vice versa.

In general, PN junction diode is fabricated with a condition

where one of its semiconductor, either P or N, is injected with higher

dopant than the other. For instance, the dopant of P-Type

semiconductor is higher than that of the N-Type semiconductor. When

those two semiconductors are mixed, the charges of each type of

semiconductors, P and N, which are accumulating on the contact

surface will eventually diffused into the other type of the

semiconductor; holes from P-Type diffuse into N-Type and vice versa.

As soon as the electron from the N-Type diffuses into the P-Type, it

leaves positive ion, whereas negative ion is formed due to the diffusion

of hole. The result is that positive ions are accumulated on the contact

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surface of the N-Type, while negative ions are accumulated on the

contact surface of the P-Type. The region which is filled with these ions

are called depletion region. This diode condition occurs at no biased

mode.

Figure 1.16 State After Contact (PN Junction Diode)

Hole and electron concentration becomes very small compared

with the concentration of the impurity on the depletion region resulted

by a very high electrostatic field. Electric field intensity directs from

the left to the right (Fig 1.15 left) or from the right to the left (Fig.6

right) due to the electric field, and this is defined as force on unit of

positive charge.

Under such condition, hole and electron will keep diffusing to

each other. If this keeps occurring, then the semiconductor which was

previously P-Type will become an N-Type and vice versa, and this is

considered as an incorrect case. The electric field created after

diffusion forces the hole and electron to return to its original place, so

that the total current in this condition has a value of zero. This will

then diffuse again and so on. Current that is resulted due to the

presence of electric field is called drift current.

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9. Bias Mode and PN Junction Diode Characteristics

There are 3 bias modes of PN junction diode, they are; no biased,

forward biased, and reverse biased. The no biased mode has already

been explained above. The forward biased mode occurs when the

diode is powered correspondingly to the polarity of the power supply

(+ve & -ve diode terminal connected with +ve & -ve terminal of power

supply accordingly). P-Type region with positive terminal and N-Type

region with negative terminal of the power supply. In reverse biased

mode, the diode is connected to the power supply with the opposite

polarity of the power supply (+ve & -ve diode terminal connected with

-ve & +ve terminal of power supply accordingly).

When diode is powered on specific voltage level in forward

biased mode, the corresponding voltage value forces the electron on N-

Type and hole on P-Type to recombine with the ions at the depletion

region. As a result, the depletion region becomes narrower. Charge

that comes from the power supply creates the P-Type to be more

positive (more number of holes) and the N-Type region to be more

negative (more number of electrons). As the potential of the power

supply increases, charges that are recombining become more and

more allowing the charges to flow in the depletion region (depletion

layer is getting more narrow). This results the majority carrier of each

region to easily passes the depletion region creating surge of current

that flows through the diode.

When diode is powered on specific voltage level in reverse

biased mode, the amount of positive ions on the depletion region are

greatly increased due to the attraction of free electrons of N-Type with

the positive potential of the voltage supply. This can be assumed when

the positive potential charge, hole, enters the N-Type region, then

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electron will fill the hole on that region. In the same manner with the

no biased mode, when electron leaves its position, positive ions will be

formed. The same explanation also applies for the P-Type region, so

that the depletion region becomes increasingly wide. The widening of

depletion region causes the majority carrier of each region to have

difficulty in passing through the depletion region which results in an

almost zero amount of current flowing.

Figure 1.17 Characteristics Curve of Diode

The above figure explains the characteristics curve of diode that

is made of different basic materials. The positive x-axis (positive V

axis) shows the condition at forward biased mode and the negative x-

axis (negative V axis) shows the condition at reverse biased mode. It

can be observed that when positive potential is given, the current does

not flow directly through the diode until the positive potential reaches

a specific value. After the positive potential reaches that specific value,

only then the current flows though the diode in which this is referred

to as on-state. When the polarity is reversed, amount of current that

19

flows through the diode will be very small nearly approaches zero and

this is referred to as off-state. However, if the potential value is kept

getting increased until a very specific high value is reached, there will

be surge of current taking place. This surge of current is caused due to

enhancement of the movement speed of the minority carriers (the

carriers that move in reverse biased mode are the minority carriers),

that is able to change the atomic structure more stable giving rise to an

additional carrier, and valence electron which experiences ionization

process. That extra carrier can help the ionization process at a point

where the corresponding current surge occurs. The area in which the

point of current surge on reverse biased mode occurs is called

breakdown region. This breakdown region point could be reduced by

increasing the dopant atom on both regions of diode. Breakdown

region has a smaller point of breakdown referred to as Zener region.

4. Practicum

For this module, the practicum will be substituted with a pre-test on

Friday, February 10th, 2017.

5. Reference

1. Modul Praktikum Rangkaian Elektronika, 2015

20

Module II

Diode


Understand the fundamental concept of PN Junction: Diode

Understand the bias mode of Diode

Understand the application of Diode


Understanding the concept of charge transfer

Understanding the bias on PN Junction

Understanding the characteristic curve of PN Junction

Understanding the equivalent circuit of PN Junction

Understanding the operating point of PN Junction on a circuit

Understanding PN Junction as rectifier

Understanding PN Junction as a voltage level converter

Understanding PN Junction as a voltage regulator

3. Basic Theory

3.1 Type and Functions of Diode

Based on the characteristics curve of diode, there are two types

of diode, namely:

1. Diode (ordinary)

Possesses main function as current rectifier and switch.

Mostly used to covert AC voltage into DC voltage by utilizing

both functions.

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2. Zener diode

Considered as a diode that works on breakdown region

with smaller point of breakdown. Possesses main function to

regulate voltage (voltage regulator).

3.2 Equivalent Circuit of Diode

There are 3 types of diode equivalent circuit:

1. Piecewise-linear

2. Simplified

3. Ideal

Figure 9. Diode Equivalent Circuit

(b) simplified

(c) ideal

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3.3 Diode Application

3.3.1. Half-Wave Rectifier Circuit

It has been explained that a diode functions mainly as a

current rectifier. HWRC is considered as a circuit with its

components composed of diodes in which the input signal is a

sinusoidal signal (AC signal) and the output is the half wave of DC

signal.

Figure 10. Half-Wave Rectifier Circuit

Figure on the left explains the input sinusoidal signal. When

input is given at interval of 0 – T/2 (positive cycle), current from the

source will flow through the diode (assumed to be ideal) because

during that respective cycle the diode is powered in forward biased

mode, so that diode is considered short and eventually voltage enters the

resistor. When input is given at interval T/2 – T (negative cycle), current

from the source does not flow through the diode because it is in reverse

biased mode, so the diode is considered as open and voltage does not enter

the resistor. If input is continued to be given, then the result will be

seen as the following figure:

23

Figure 11. Result of HWRC

3.3.2. Full-Wave Rectifier Circuit

FWRC is a circuit where its components consist of diodes

where the input signal is a sinusoidal signal (AC) and the output

signal is a full wave DC signal.

Figure 13. Full-Wave Rectifier Circuit

The working principle of FWRC is similar to HWRC,

however, in FWRC the diode should be analyzed first to decide

which diode is open and which diode is close. The result is that

the resistor polarity (output) does not change, either on the

positive cycle or the negative cycle, producing the result as a full

wave.

24

Figure 14. Result of FWRC

3.3.3. Clippers Circuit

CC is a circuit where the components consist of a diode

that has a function to shift the level of polarity turnover from the

given input signal into the circuit and clamps (forces) the output

voltage value constant on a specific value on specific input signal

cycle. There are two types of CC configuration, that is, input

signal connected in series with the diode and the one connected

in parallel. HWRC is considered as CC that is connected in series.

Figure 16. Series (left) & Parallel (right) of Clippers Circuit

In series configuration, the DC supply is connected in the

same direction with the diode. When the positive input enters

the circuit and if the value is less than the DC supply, then the

diode is in the on-state. By using the KVL rule, the output value

could eventually be obtained. When the value exceeds the DC

supply’s, the diode is in the off-state, so that the output value is 0

V. In this case, CC acts as the shifter of the level of polarity

turnover from the given input signal.

25

In the parallel configuration, the DC supply is attached

opposite in direction to that of the diode. When the positive

input enters the circuit, the diode is on, so that it is considered

close. As the output is connected parallel with the DC supply,

then the output value is equal to that of the DC supply if the

input value exceeds the DC supply’s. When the input is negative,

then the output value will be the same as the input value.

3.3.4. Clampers Circuit

CLC is considered as a circuit which comprises of diode as

well as capacitor that shifts the input voltage level without

changing the original form. For instance, if the input sinusoidal

signal has an amplitude of 20 V (peak-to-peak 40V), then the

output voltage level is the result of shifting of the input signal

with peak-to-peak that is constant (40 V).

Figure 18. Clampers Circuit

First step is to assume the initial state of diode. In the

above figure, it is seen that the diode is on the positive cycle.

During this cycle, the capacitor will undergo charging until it has

26

a value equal to that of the input during period т = RC. So that,

the circuit can function well by fulfilling the period of the input

signal.

In the above figure, RC has a small value because the

resistor is shorted due to diode. The value of output is 0 V due to

the parallel attachment with the diode.

During the negative cycle, the capacitor will experience

discharging and the diode will eventually be in the off-state. The

output value can be obtained by applying the KVL rule in which

the value is the total of input signal and capacitor. The clamping

result is shown in the figure at the top right corner.

3.3.5. Voltage Regulator Circuit

VRC is considered as a circuit which applies Zener diode in

order to regulate the voltage output.

Figure 20. Voltage Regulator Circuit

Compared to the other circuit, VRC uses the DC supply so

that the current passes through the diode in one direction only.

The analysis of this circuit starts by assuming that the Zener

diode is in the open state. Then, the output value is calculated by

using the KVL rule. The Zener diode has a voltage specification

that is constant. If the output value is equal to or more than the

Zener diode voltage, then the Zener diode is in active state and

27

its output value is equal to the Zener diode voltage value due to

its parallel connection. If it is less, then the Zener diode becomes

off.

4. Practicum

HALF-WAVE RECTIFIER CIRCUIT EXPERIMENT

Tools and Equipments:

o 1 protoboard & oscilloscope

o 1 diode (1N4002 / 1N4007 / 1N4148)

o 1 resistor (10K)

Experiment Steps:

1. Arrange the circuit as shown in figure 12!

2. Connect the jumper cable on the 12V AC generator, then connect it

to the anode of the diode!

3. Connect the jumper cable on the 0V AC Generator, then connect it

to the ground!

4. Connect the jumper cable at the cathode of the diode, then connect

them with probe & oscilloscope!

5. Connect the jumper cable at the ground terminal, then connect

them with the probe - oscilloscope!

6. When done, ask for assistance to check the circuit!

7. Power up the protoboard only when the assistant gives

permission to use the circuit!

8. Observe the result on the oscilloscope!

28

Figure 12. HWRC Circuit Experiment

FULL-WAVE RECTIFIER CIRCUIT EXPERIMENT



o 4 diodes (1N4002 / 1N4007 / 1N4148)

o 1 resistor (10K)

Experiment Steps:


2. Connect the jumper cable on the 12V AC generator, then create a

node connecting D12 and D13!

3. Connect the jumper cable on the 0V AC generator, then create a

node connecting D14 and D15!

4. Connect the jumper cable at the cathode of the diode, then connect

them with probe & oscilloscope!

5. Connect the jumper cable at the ground terminal, then connect

them with the probe - oscilloscope!

6. When done, ask for assistance to check the circuit!

7. Power up the protoboard only when the assistant gives

permission to use the circuit!

29

8. Observe the result on the oscilloscope!

Figure 15. FWRC Circuit Experiment

CLIPPERS CIRCUIT EXPERIMENT



o 1 dioda (1N4002 / 1N4007)

o 1 resistor (10K)

o 1 resistor (1K)

o 1 DC Supply

Experiment Steps:


2. Follow the steps of HWRC!

3. Repeat the experiment by inversing the direction of the diode!

30

Figure 17. Clippers Circuit Experiment

CLAMPERS CIRCUIT EXPERIMENT



o 1 diode (1N4002 / 1N4007)

o 1 resistor (22K)

o 1 DC Supply

o 1 capacitor (10 uF)

Experiment Steps:


2. Follow the steps of HWRC!

3. Repeat the experiment by inversing the direction of the diode!


Figure 19. Positive Clampers Circuit Experiment

31

Figure 20. Negative Clampers Circuit Experiment

Figure 21. Negative DC Bias Clampers Circuit Experiment

VOLTAGE REGULATOR CIRCUIT EXPERIMENT Tools and Equipments:


o 1 zener diode (1N4732)

o 1 resistor (10K)

o 1 resistor (100K)

o 1 DC Supply

32

Experiment Steps:

o Arrange the circuit as shown in figure 22!

o Follow the steps of HWRC!

Figure 22. Voltage Regulator Circuit Experiment

Note: Study all the written materials of the basic theory

bullet points. Understanding of each written materials is

OBLIGATORY, and will be tested before the practicum begins.

All of the laboratory assistants have the right to give

punishments to the students who do not study the materials

beforehand.

5. References

Boylestad, Robert L., Nashelsky, Louis. 2013. ELECTRONIC

DEVICES & CIRCUIT THEORY, Eleventh Edition. United States :

Pearson.

Kano, Kanaan. - . SEMICONDUCTOR DEVICES. United States :

Prentice Hall

Pierret, R. F.. 1996 . SEMICONDUCTOR DEVICES FUNDAMENTALS.

- : Addison Weasley.

33

Module III

Bipolar Junction Transistor (BJT)


Understand the working principle of bipolar junction transistor

Observe and understand the DC Biased on transistor

Observe and understand the working principle of Bipolar transistor as

amplifier

Observe circuit principle of the logic circuit through BJT


Definition of Bipolar Junction Transistor

Explanation of BJT Band Diagram

Working Principle of PNP type and NPN type BJT

Characteristics of each BJT circuit configuration

BJT Symbol, Packaging, and Terminal Identification

BJT application on Logic Gate (NOT, AND, OR, NAND, NOR)

Datasheet summary of BJT BC-107

3. Basic Theory

3.1. Introduction

Transistor is a semiconductor device that functions as a current,

voltage, and signal amplifier. BJT (Bipolar Junction Transistor) is one of the

most used transistors. The term ‘Bipolar’ means that the transistor

includes both electrons and holes in its operation, while other types of

transistor only include either electrons or holes. Whereas, if the process

involves only one carrier (either electron or hole), then it is called unipolar.

34

BJT is a 3-layer transistor consisting of 2 n-type layers and 1 p-type

layer (NPN transistor) or 2 p-type layers and 1 n-type layer (PNP layer).

BJT layers consist of emitter, base, and collector. Emitter acts as the source

of majority carrier and is heavily doped (1019/cm3). Base is doped lightly

and made as thin layer in order to make small transient time and prevent

recombination. Collector is doped less heavily than transistor but its layer

made larger in order to reduce dissipation.

3.2. Working Principle of Bipolar Junction Transistor

Figure 1. The flow of majority and minority carrier in PNP transistor

The working principle of above BJT is described by using the minority

and majority carriers on PNP-type BJT. By observing closely, it is seen that

there are two p-n junctions having depletion region of different width on

BJT. In forward active mode, one of the p-n junction of a transistor is given

forward biased while the other is given reverse biased. When the the two

p-n junction are given potential voltage, there will be flow of minority and

majority carrier occurring. As explained in the previous module about p-n

junction process, when p-n junction is given forward biased then a number

of majority carrier will diffuse from p type to n type material due to narrow

depletion layer. Carriers that diffuse will directly contribute to the base

35

current IB or directly heading to p-type material. Due to n-type material

having small thickness and low conductivity, the current flowing towards

the base terminal will be very small. The majority carrier will act as

minority carrier when it is in n-type material. It can be said that minority

carrier injection has occurred in n-type material. Therefore, all of the

minority carrier in depletion region (base-collector) will pass thorough the

reverse-biased junction which eventually heading towards the collector

terminal or referred to as drift current.

Figure 2. PNP Transistor Band Diagram

3.3. Bipolar Junction Transistor Configuration

Basically, the bipolar transistor is used as amplifier which consists of

three basic configurations, namely; common base, common emitter, dan

common collector.

3.3.1. Common Base Configuration

By its name, the term Common Base configuration is referred to

a configuration in which the Base pin is connected to the ground

terminal and is used in conjunction either for input or output. In

Common Base configuration, the input signal is inserted into the

Emitter and its output signal is taken from the Collector, while the

36

Base is connected to ground terminal. Thus, the term Common Base

is often referred to as “Grounded Base”.

Figure 3. Common Base Configuration (PNP)

This Common Base Configuration results in Voltage

amplification between the input and output signal, yet it does not

result in current amplification.

3.3.2. Common Emitter Configuration

Common Emitter is one of the three transistor configuration in

which the Emitter pin is grounded and is being used for the input

and output. In Common Emitter configuration the input signal is

inserted to the Base and the output signal is obtained from the

Collector pin.

37

Figure 4. Common Emitter Configuration (PNP)

The Common Emitter configuration or shared Emitter is

considered as one of transistor configuration that is mostly used,

mainly on amplifier which requires voltage and current

amplification simultaneously. This is due to the transistor

configuration of this kind to produce voltage amplification and

current amplification between the input and output signal.

3.3.3. Common Collector Configuration

On a Common Collector configuration, its input is connected to

the transistor base while its output is obtained from the transistor

emitter while its collector is grounded and is used together either

for the input or the output.

38

Figure 5. Common Collector Configuration (PNP)

This Common Collector configuration or shared Collector

possesses behavior and function that are opposite to that of a

common Base. If Common Base could result in voltage amplification

without amplifying the current, then this Common Collector has a

function which could produce current amplification without its

voltage getting amplified.

39

3.4. BJT AC Analysis

3.4.1. BJT Transistor Modeling

Model is an approach towards combination of electronics circuit

combination chosen to describe or illustrate how a semiconductor

component works under certain conditions or circumstances.

Untuk menentukan parameter dari tiap rangkaian, dapat To

determine the parameter of each circuit, kutub empat method

could be used empat.

Equivalent AC circuit of a transistor could be obtained by applying

the steps below:

1. Replace all DC source to zero (ground) and replace it with

equivalent short-circuit.

2. Replace all of the capacitor with short-cicuit.

40

3. Take out all of the elements which has been passed by the

components that have been changed into short-circuit according in

step 1 & 2.

4. Make the circuit diagram neat, so that it is more easy to

understand.

3.4.2. Transistor Model re (Common Emitter)

1. Determine the equivalent circuit of BJT

2. Determine the value of Zi

41

So that the circuit could be spruced up as shown below:

3. Determine the initial voltage value and the output impedance

42

The “Q” sign indicates that the voltage position begins to have a

steady rise. However, due to VA having a value way more than

that of VCEQ, then it can be written as:

Or gradient method can be applied (Slope of the line)

So that the equivalent circuit finally looks as below

43

3.4.3. Fixed Bias Common Emitter Configuration

The fixed-bias circuit on figure 4.2 is considered as the most

simplest DC bias transistor. Although the circuit uses an npn

transistor, all of the equation and calculation are similar just like

when using a pnp transistor configuration with only changing all

of its direction of current and its polarity of voltage.

All of the direction of current on figure 4.2 are the actual current

directions, and the voltages are defnined as double-subscript

standard notation. Fo DC analysis, the circuit could be isolated

from the AC signal by replacing the corresponding capacitors with

an equivalent open circuit because basically the reactance of a

44

capacitor is a function of the applied frequency. For DC,

.

Moreover, DC source Vcc could be split into two sources as

shown in figure 4.3 in order to allow a seperation from the input

and ouput circuit. Such separation could as well reduce the

relation between the two sources with respect to base current .

45

Steps of Parameter Calculation on Fixed Bias CE:

1. Change the original circuit into an equivalent circuit form

2. Determine input and output impedance (Zi & Zo)

46

3. Determine voltage gain (Av)

The “minus” sign is due to inverted Io polarity βIb.

3.4.4. Voltage Divider Bias Common Emitter Configuration

This configuration uses two resistors as potential difference

divider on voltage supply in order to supply an amount of voltage

required by the base of BJT. This configuration is commonly used

as an amplifier circuit.

By using this method, the effect resulted from difference in beta

value (β) is vastly reduced by restraining the bias on the base with

a constant value of voltage, so that a proper stability is achieved.

The voltage value on Base (Vb) is specified by the voltage divider

47

formed by the two resistors (R1 & R2) as well as the voltage source

(Vcc).

Steps of Parameter Calculation on Fixed Bias CE:

1. Change the original circuit into an equivalent circuit

2. Determine Thevenn resistance (Rth) at the base of BJT

3. Determine input and output impedance (Zi & Zo)

48

4. Determine the voltage gain (Av)

4. Practicum


o Power supply DC

o Multimeter

o Oscilloscope

o Bread board

o LED

o Resistor

o BC107

49

Voltage Divider Common Emitter

Figure 1. (a) Common-emitter Circuit (b) Equivalent Circuit

Connect the amplifier circuit CE to the function generator as in

Figure 4. Adjust it so that V1 = 10 volt and f = 1 kHz.

Figure 2. Transformation Circuit CE-1

Repeat the above step with different frequencies.

Logic Circuit

Aside from being used for amplifier circuit, transistor is often used in

switching process. In general, switching process is used in digital

application, that is to assemble logic gates circuit.

50

o NOT Gate

o AND Gate

51

o OR Gate

o NAND Gate

52

o NOR Gate

Connect the NOT logic circuit as shown in the above figure.

Carefully observe the output (indicated by the on or off state of the

LED) for each input combination.

Write down the result on a given piece of paper.

5. BJT BC 107 Data Sheet

Philips Semiconductors Product specification

NPN general purpose transistors BC107; BC108; BC109

FEATURES

Low current (max. 100 mA)

Low voltage (max. 45 V).

APPLICATIONS General purpose switching and amplification.

DESCRIPTION NPN transistor in a TO-18; SOT18 metal package. PNP complement: BC177.

53

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT

VCBO collector-base voltage open emitter

BC107 50 V

BC108; BC109 30 V

VCEO collector-emitter voltage open base

BC107 45 V

BC108; BC109 20 V

ICM peak collector current 200 mA P

tot total power dissipation Tamb 25 C 300 mW h

FE DC current gain IC = 2 mA; VCE = 5 V BC107 110 450

BC108 110 800

BC109 200 800

fT transition frequency IC = 10 mA; VCE = 5 V; f = 100 MHz 100 MHz

54

6. References

Boylestad, Robert L., Nashelsky, Louis. 2013. ELECTRONIC DEVICES &

CIRCUIT THEORY, Eleventh Edition. United States : Pearson.

Alexander, Charles K., Sadiku, Matthew N.O. (2009). Fundamental of

Electric Circuit ( Fourth Edition). New York : McGraw-Hill.

Floyd.2001. “Electronics Fundamentals Circuit, Devices, and

Application”.New Jersey:Printice Hall, Inc.

http://hyperphysics.phy-

astr.gsu.edu/hbase/electronic/opampi.html#c2

http://www.electronics-tutorials.ws/amplifier/amp_2.html

BJT Datasheet Catalog – BC107

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/opampi.html#c2

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/opampi.html#c2

http://www.electronics-tutorials.ws/amplifier/amp_2.html

55

Module IV

Field Effect Transistor (FET)


Understand working principle of JFET and MOSFET.

Observe and understand DC bias on JFET and MOSFET.

Observe and understand working principle of JFET and E-MOSFET as

amplifier.


Definiton of FET

Working Principle of FET

Difference between BJT dan FET

Types of FET (Construction and Characteristic Curve)

AC Analysis of FET

3. Basic Theory

3.1. Definition

FET (Field Effect Trasistor) is an active electronic component

that is commonly used as an amplifier as well as a switching circuit.

FET is considered as a type of transistor that uses electric field

effect in in its application as amplifier or as switching circuit and is

referred to a unipolar component.

56

3.2. Difference of FET and BJT

Figure 1. BJT as current regulator and FET as voltage regulator

FET BJT

Transform voltage into current

Transform current into current

VCCS CCCS

Unipolar Bipolar

Faster switching Slower switching

3.3. Types of FET

3.3.1. Junction Field Effect Transistor (J-FET)

Construction

57

JFET is a semiconductor device which consists of three

terminals in which one of the terminals has an ability to

control current on the other terminals. The above figure is

an n-type JFET on the channel part and a p-type material

that forms the depletion region. At the top part there is

drain (D) and the bottom part there is source (S) that is

connected with the ohmic contact. The two parts of p-type

material is connected with the gate terminal (G). As for the

working principle of JFET, it will be explained by using the

following charactersistic and transfer curve.

58

Transfer Curve and Characteristic

In the above figure of transfer curve and characteristic,

it is clearly observed that the positive voltage is given on

VDS and VGS = 0V resulting in gate condition and source to

have the same potential and the resulted depletion region

is very low in which current is eventually able to flow.

59

Pinch-off condition is a condition when current from

the source to the drain is not able to flow due to the

increasing of the depletion region on p-type material. (VGS

= 0V, VDS = VP)

60

Significant Formulas

61

3.3.2. Depletion-type MOSFET (D-MOSFET)

Construction

The above figure shows the construction of an n-

channel depletion-type MOSFET. The p-type substrate is

made from silicon. The source and drain terminals are

connected with the metal part as their contacts. The gate

terminal is as well connected to the metal contact, but is it

is different from the previous ones, because in this case

there is an insulator layer (SiO2) which has a function in

avoiding any direct electrical connection between the gate

and the channel on MOSFET. The working principle of D-

MOSFET is shown below along with the transfer curve and

the characteristic.

62


The VGS voltage is given 0V with direct connection

from one of the terminal to the other. VDD voltage is

connected with the drain-source terminal. The result is the

attraction of free electrons on n-channel with positive

voltage at drain terminal. Current is resulted just as similar

as the JFET through the channel. The resulted current with

VGS = 0V is IDSS.

63

When D-MOSFET is given negative voltage at the gate

terminal, then free electrons at the gate will be reduced.

This is due to when negative voltage is given, the electrons

will move away from the channel towards p-substrate and

cause recombination with the hole to occur.

3.3.3. Enhancement-type MOSFET (E-MOSFET)

Construction

64

Although by construction E-MOSFET has a similarity

with D-MOSFET, they differ in characteristic. The transfer

curve of E-MOSFET is not specified based on Shockley

equation, and current from source to drain will not flow

until a minimum voltage on the gate-source terminal is

reached.

The difference on the construction of E-MOSFET is

observed by the absence of channel that connects source

and drain. Hoever, metal contact is still used on the source

and the drain terminal. The gate is limited by the presence

of SiO2 insulator. Apart from difference of the channel,

other part of E-MOSFET are similar to that of D-MOSFET.

How current is able to flow from source to drain in an E-

MOSFET will be explained below.


65

From the graph, it is clearly observed there is a

difference in its transfer curve, that is, the presence of VT

as the minimum voltage so that E-MOSFET could operate.

The limit voltage or threshold is considered as the

required minimum voltage of E-MOSFET, so that channel

between source-drain could be formed. Electron is pulled

upward when gate is given positive voltage and depletion

region pushes the holes in order to act as a boundary with

the p-substrate.

Significant Formulas

66

How to Measure IDSS

1. The Gate and Source pins are short linked.

2. Connect the negative pole (-) of power supply to Gate

and Source node.

3. Connect the negative cable (-) of multimeter to Drain

pin of the JFET.

4. Connect the positive cable (+) of multimeter to positive

pole (+) of the battery.

5. Do not forget to set the multimeter on mA.

AC FET Equivalent Circuit

After doing the DC analysis on FET and making sure that

the FET is working on saturation condition (active), AC

analysis is then used to observe how big is the

current/voltage amplification that is resulted by the FET.

The form of AC equivalent circuit of JFET is shown below.

67

4. Practicum

Experiment Steps

1. Arrange the circuit as shown below.

2. Measure Va, Vb, IDSS, VP, and VT.

68

o J-FET Common Drain

o E-MOSFET Common Source

69

Module V

Frequency Response of Bipolar Junction Transistor (BJT)


Understand frequency response analysis by using bode plot

Understanding low frequency response for BJT amplification

Understanding high frequency response for BJT amplification


Decibel and bode diagram

Frequency response

Frequency response at BJTs voltage divider circuit

DC and AC analysis (high and low frequency) for BJT circuit

Capacitance which occurs on BJT circuit

Characteristic curve toward the amplification of BJT circuit

3. Basic Theory

3.1 Decibel

Decibel (dB) is a unit for power or audio which relates to the

logarithm basis of output and input from a system. It can be

written as follows

70

or from the ratio of voltage can be written as

The ratio with Decibel unit usually used to acknowledge the

amplification of a system (Av) where the result could either be

strengthening (>0dB) or weakening (<0dB). It relates to the

frequency analysis and bode plot. The ratio of input and output

could be observed at the following table

Table 5.1 Ratio of Av = Vo/Vi towards Db

3.2 Bode Diagram

It is a method by using graph analysis in the region of

frequency so that one could easily specified the characteristic of

the circuit occurs on a certain frequency. Creating the bode

diagram typically using semilog paper. Graph shown in Figure

5.1 shows change in one decade on the horizontal side that

71

shows frequency, and usually on the vertical side of the unit is

given to show Magnitude dB, either strengthening or weakening.

Figure 5.1 Bode plot

3.3 Frequency Response

Frequency Response is a phenomenon occurs on the circuit

occurs on the value of the frequency given on the circuit. At low

frequency and high frequency, there is a bypass and coupling

capacitors that cannot be replaced again with the approach of

short circuit or open circuit reactance due to the addition of the

element. In this chapter, the method is no longer carried out so

that the capacitance value calculation will be used.

.

3.4 Frequency Response of BJT Voltage Divider

The circuit to be used for this experiment is voltage divider BJT

on figure 5.2. There are C3 (Cin), C2 (Cout), C1 (CE) where the

experiment is done to observe the response of the BJT circuit

towards the variation of frequency given.

72

Figure 5.2 BJT Voltage Divider Circuit

At the DC analysis where the frequency is equals to 0, then the

capacitor C1, C2 and C3 would be consider as open circuit

because of its reactance which is infinite. But on the AC analysis,

there occurs the effect of the capacitor for every level of

frequency which differs from low, mid and high frequency.

Before continuing the analysis, it is important to know about

the naming of the capacitor and its location. Basically there are 2

types of capacitor which is:

Practical capacitor: Cin, Cout, CE which as explained before, it

has physical presence and mounted inside the circuit on

Figure 5.2.

Virtual capacitor: Cwi, Cwo, CBE, CBC, CCE these capacitor

does not have any physical presence, but there will be

capacitance between the feet of its transistor as the result of

the miller effect.

73

The virtual capacitor could be seen from Figure 5.3. There must

be another measurement using LCR meter to analyze the

capacitance between the foot of the transistor and input

capacitance & output to the ground.

Figure 5.3 Virtual Capacitor

Next, the frequency variation will produce different

reinforcement at each frequency. The curve between the

amplification (Vo / Vi) against frequency is shown in Figure 5.4.

In this experiment, bode curve is applied to get accurate results.

Figure 5.4 Frequency Response of BJT Amplification

74

At Figure 5.4 there occurs fc1 and fc2 where it represents as

the low cut off frequency and high cut off frequency. Cut off

frequency is where the amplification would get down around

0.707 (-3dB) from its stable condition. Hence, in this experiment

we will study the response of a system to variations of a given

frequency. This circuit has a similar function as a filter that will

be studied at the active filter module.

4. Practicum

BJT Voltage Divider Circuit

1. Arrange the components according to the figure given. Make sure

there are no short circuit occurs.

2. Connect the circuit with multimeter to measured Ib and Ic using

the tweezers cable and jumper cable. Make sure the multimeter

75

installed correctly (series to measured current). Make sure the

port used at the multimeter is installed correctly (DC current port

to measured Ib (0.3 mA) and Ic (30 mA).

3. Connect the function generator with multimeter and then let the

function generator on. Set the frequency to be 50 Hz and also the

amplitude of the function generator, so we could obtain the Vs

value that we want.

4. After obtaining the wanted Vs value, connect Vs and VCC (15V)

from the function generator to the circuit. Measured Va (VAC) and

Vb (VAC) then measured the Ib current (A DC) and Ic (A DC) using

multimeter.

5. Repeat steps 3 & 4 by using different frequency.

6. Return the source to 1KHz frequency then measured the

capacitance of Cwi and Cwo using LCR meter.

7. After finished, take out the BJT and measured the capacitance

between the BJTs BE, EC and BC feet by using LCR meter.

76

5. Reference

1. Boylestad, Robert., Louis Nashelsky, “Electronic Devices and

Circuit Theory : eleventh Edition”, Prentice Hall International

Editions, 2013

77

Module VI

Frequency Response of Field Effect Transistor (FET)


Understand frequency response analysis by using bode plot

Understand low frequency response for FETs amplification

Understand high frequency response for FETs amplification


Decibel and bode diagram

Frequency response

Frequency response at FETs voltage divider circuit

DC and AC analysis (high and low frequency) for FETs circuit

Capacitance occurs on FET circuit

Characteristic curve toward the amplification of FET circuit

The resume of JFET 2N5457 datasheet

3. Basic Theory

3.1 Desibel

Decibel (dB) is a unit for power or audio which relates to the

logarithm basis of output and input from a system. It can be

written as

78

or from the ratio of voltage can be written as

The ratio with Decibel unit usually used to acknowledge the

amplification of a system (Av) where the result could either be

strengthening (>0dB) or weakening (<0dB). It relates to the

frequency analysis and bode plot. The ratio of input and output

could be observed at the following table:

table 5.1 Ratio Av = Vo/Vi towards Db

3.2 Bode Diagram

It is the method by using graph analysis in the region of

frequency so that one could easily specified the characteristic of

the circuit occurs on a certain frequency. Creating the bode

79

diagram typically using semilog paper. Graph shown in Figure

5.1 shows change in one decade on the horizontal side that

shows frequency, and usually on the vertical side of the unit is

given to show Magnitude dB, either strengthening or weakening.

Figure 6.1 Bode plot

3.3 Frequency Response

Frequency Response is a phenomenon occurs on the circuit

occurs on the value of the frequency given on the circuit. At low

frequency and high frequency, there is a bypass and coupling

capacitors that cannot be replaced again with the approach of

short circuit or open circuit reactance due to the addition of the

element. In this chapter, the method is no longer carried out so

that the capacitance value calculation will be used.

80

3.4 Low Frequency Response of FET Amplifier

There are 3 capacitor CG, CC, CS where CG and CS is a coupling

capacitor while Cs is a bypass capacitor. The circuit used on this

experiment is done to observe the response of the FET circuit

towards the variation of the given frequency.

Figure 6.2 Self-bias FET circuit

At DC analysis where the frequency is equals to 0, then the

capacitor CG, CC and CS would be considered as open circuit

since its reactance is infinite. But on the AC analysis, there would

be another effect from the frequency for every different level

which is low, mid and high.

Before continuing the analysis, it is important to know about

the naming of the capacitor and its location. Basically there are 2

types of capacitor which is:

Practical capacitor: CG, CC, CS which as explained before, it

has physical presence and mounted inside the circuit on

Figure 6.2.

Virtual capacitor: Cwi, Cwo, CBE, CBC, CCE these capacitor

does not have any physical presence, but there will be

81

capacitance between the feet of its transistor as the result of

the miller effect (between Gate-Drain junction with high

frequency at common source FET amplification circuit).

The virtual capacitor could be seen from Figure 5.3. There must

be another measurement using LCR meter to analyze the

capacitance between the foot of the transistor and input

capacitance & output to the ground.

3.5 High Frequency Response Circuit of FET Amplifier

Figure 6.3 Virtual Capacitor

Next, the frequency variation will produce different

reinforcement at each frequency. The curve between the

amplification (Vo / Vi) against frequency is shown in Figure 5.4.

In this experiment, bode curve is applied to get accurate results.

82

Figure 6.4 FET Amplifier Frequency Response

At Figure 6.4 there occurs fc1 and fc2 where it represents as

the low cut off frequency and high cut off frequency. Cut off

frequency is where the amplification would get down around

0.707 (-3dB) from its stable condition. Hence, in this experiment

we will study the response of a system to variations of a given

frequency. This circuit has a similar function as a filter that will

be studied at the active filter module.

83

4. Experiment

Self Bias FET Circuit

1. Arrange the components according to the Figure given. Make sure

the there are no short happened and the transistor feet is applied

correctly.

2. Connect the circuit using multimeter to measured Vi, Vo, IDSS and

VP by using tweezers and jumper cable.

3. Connect the function generator with multimeter, and then turn on

the function generator. Set the frequency to be 50 Hz and also its

amplitude on the function generator so the Vs value is according

to what we want.

84

4. After the Vs is being set, connect Vs with VCC from the function

generator to the circuit. Measured Vi, Vo, IDSS current and Vp by

using multimeter.

5. Repeat steps 3-4 by changing it to different frequency.

6. Return the source to 1 Khz frequency, measured the Cwi and Cwo

capacitance using LCR meter.

7. After finished, take out the FET and measured the capacitance

between Cgd, Cgs and Cds feet by using LCR meter.

5. References

1. Alexander, Charles K., Sadiku, Matthew N.O. (2009). Fundamental

of Electric Circuit ( Fourth Edition). New York : McGraw-Hill.

2. Boylestad, Robert., Louis Nashelsky, “Electronic Devices and

Circuit Theory : eleventh Edition”, Prentice Hall International

Editions, 2013

85

Module VII

Operational Amplifier


Understand how op-amp works as an amplifier

Understand inverting and non-inverting amplifier on op-amp

Understand integration dan differentiation of sinusoidal and non-

sinusoidal waveform as well as its effect on amplitude and phase

angle


Know the characteristic of op-amp

Know the symbol and circuit in op-amp

Know what is offset voltage in op-amp

Know the types of op-amp circuit

Know inverting dan non-inverting circuit on op-amp

Know how amplifier circuit works

Know how comparator circuit works

Know the term unity gain for differentiator and integrator circuit

Know how differentiator and integrator circuit works

3. Basic Theory

3.1. Introduction

Operational Amplifier or op-amp is a voltage amplifying device

that is generally used with external component such as resistor or

capacitor on its input and output terminal. By combining the use of

resistor, capacitor, or both, op-amp can do various function or

operation. Op-amp is generally integrated in an Integrated

Circuit(IC). Some example of op-amp IC are LM 741, TL071, LM311,

86

and some variation from the three can be powered by sing single

power supply or dual power supply, or from how many op-amp are

integrated in one IC (single, dual, or quadruple).

Op-amp is generally analysed as an ideal op-amp. This is

possible because the IC on op-amp is generally functioning as an

ideal op-amp. Ideal op-amp have three important terminals which

are Inverting Input, generally given a minus sign (-); Non-inverting

Input, generally given a plus sign (+); dan Output. An op-amp IC

have two extra terminals for power supply, Vcc+ and Vcc- for dual

power supply Op-Amp or Vcc+ and GND for Single Power Supply op-

amp.

The following are the ideal op-amp characteristics that are

useful for analyzing the working principle of an op-amp:

Infinite Voltage Gain

Voltage gain is not dependent upon the specification of an op-

amp, but rather by the circuit configuration so that voltage gain

can be adjusted as needed.

Infinite Input Impedance

Infinite input impedance causes no current to flow into the two-

input terminal

87

Output impedance is zero

Infinite Bandwidth

Bandwidth have a certain frequency range that are allowed to

pass. This characteristic is usually used in filter design.

Bandwidth circuit is configured through circuit configuration so

that bandwidth can be adjusted as needed.

Offset voltage is zero

Offset voltage is the voltage on the output when the given input

voltage is zero.

3.2. Ideal Op-Amp

To perform the analysis on the op-amp, an approach towards

the ideal op-amp is used where each of its characteristics are

known. The following is the image of an ideal op-amp:

Figure 3. Idel Op-Amp

1. Current on each of the two terminal inputs (inverting and

noninverting) are zero

88

This occurred because the input resistance on the open loop

circuit is infinite so there is no current flowing inside the op-

amp. But output current is not zero.

2. The voltage between the input terminal is equal to zero

In ideal op-amp, there is no current flowing inside the op-amp

so the voltage between the input terminal is also zero. Thus, the

voltage on the inverting and non-inverting input are the same.

3.3. Inverting Amplifier

In this session, the application of op-amp as an inverting

amplifier is discussed. Non-inverting input is connected to the

ground. Vi is connected to the resistor R1 and the feedback resistor

Rf is connected to Vo.

Figure 4. Inverting Op-Amp Amplifier

89

By applying KCL on node 1 then

As explained before on an ideal op-amp, V1 = V2. V2 is connected to

the ground where the voltage 0 V so that V1 = V2 = 0V. Thus, the

equation becomes

So, the obtained gain is Av= Vo/Vi = -Rf/Ri. The output is found

to be negative, which means that the output will have opposing

polarity compared to the input.

3.4. Noninverting Amplifier

Another application of op-amp is non-inverting amplifier

circuit where the input is directly given to non-inverting terminal.

Resistor R1 is given between inverting terminal and ground while

Rf as feedback between inverting input and output.

Figure 5. Non-Inverting Op-Amp Amplifier

90

Apply KCL on inverting terminal so that

On ideal op-amp V1=V2 where V2 is equal to Vinput so that

V1=V2=Vi

atau

So, the obtained gain is A = Vo/Vi = 1+ Rf/Ri. There is no differing

sign between the input and output, so the polarity between them is

the same.

On another condition, op-amp is used as intermediate stage

(buffer) where the gain is 1 (Rf =0, R1=∞). This circuit is called

voltage follower (or unity gain amplifier). The voltage on voltage

follower circuit is

Figure 6. Voltage Follower

91

Voltage follower circuit (buffer) is used to isolate a circuit from

another circuit. This circuit minimize the interaction between 2

circuits and eliminate interstage loading.

Gambar 7. Voltage follower is used to isolate two cascaded circuit

Besides a voltage amplifier, the op-amp IC is also commonly

used as a comparator. The comparator can compare the input to the

inverting input and non-inverting input. The thing that occurs is the

voltage difference between the two inputs strengthened in

accordance with the open loop voltage gain (open loop gain). The

amplification is generally greater than 100 so that the output

voltage becomes saturated, so there are only 2 possible outputs,

namely positive voltage approaching +Vcc and negative voltage

approaching -Vcc.

Figure 4. Ideal Integrator Ideal and Differentiator Circuit

92

Kirchoff Law I on Integrator Circuit

𝑣𝑖𝑛(𝑡) − 0

𝑅= 𝐶

𝑑(0 − 𝑣𝑜(𝑡))

𝑑𝑡

𝑣𝑖𝑛(𝑡)

𝑅= −𝐶

𝑑𝑣0(𝑡)

𝑑𝑡

𝑑𝑣𝑜(𝑡) = −1

𝑅𝐶𝑣𝑖𝑛(𝑡)𝑑𝑡

Kirchoff Law I on Differentiator Circuit

𝐶𝑑(𝑣𝑖𝑛(𝑡) − 0)

𝑑𝑡=

0 − 𝑣𝑜(𝑡)

𝑅

In addition to using an external resistor as a component of an

op-amp circuit, a capacitor may also be used. Capacitors, which

can pass current in accordance with changes in voltage versus

time (differentiation), can make the op-amp circuit known as

differentiator and integrator. The circuit in the picture above is a

series integrator and differentiator. This circuit can perform

operations like integral or differential to an input waveform. This

circuit has a transition frequency in which the separation of

frequency occurs when the wave is given amplification and when

the wave is integrated/differentiated. In reality, ideal

differentiator is not practically used because its susceptibility

towards high frequency noise is amplified because the frequency

𝑣𝑜(𝑡) = −1

𝑅𝐶∫ 𝑣𝑖𝑛(𝑡)𝑑𝑡 + 𝑣𝑜(0)

𝑡

0

𝑣𝑜(𝑡) = −𝑅𝐶𝑑𝑣𝑖𝑛(𝑡)

𝑑𝑡

93

response from the ideal differentiator circuit is further

strengthened when the frequency is high [3].

Figure 5. The result of the wave is differential from the DC input

pulse

Op-Amp 741 DataSheet

Figure 8. Pinout IC 741

94

4. Practicum

Inverting Amplifier

Experiment Steps:

1. Arrange the circuit as shown above. The resistance of R1 and R2

will be given by the laboratory assistant

2. Create a sinusoidal wave with an amplitude and frequency

determined by a laboratory assistant on the Signal Generator.

3. Observe and record the value of the output voltage that is

indicated on the oscilloscope and measuring device

4. Repeat step 2 and 3 with different input voltage

95

Non-inverting Amplifier

Experiment Steps:

1. Arrange the circuit as shown above. The resistance of R1 and R2

will be given by the laboratory assistant.

2. Create a sinusoidal wave with an amplitude and frequency

determined by a laboratory assistant on the Signal Generator.

3. Observe and record the value of the output voltage that is

indicated on the oscilloscope and measuring device.

4. Repeat steps 2 and 3 with different input voltage.

96

Integrator Circuit Experiment

Experiment Steps:

1. Arrange the circuit as shown above. Use R9 as 1K and R10 as 10K,

C1 as 10nF dan Power Supply as +/-15V

2. Adjust the signal generator to produce a square wave with V=3

Vp-p and a frequency of 10 Hz

3. Observe the input and output wave on the oscilloscope

4. Repeat 2 and 3 for a frequency of 14kHz

5. Repeat step 2, 3, and 4 for triangle and sinusoidal wave

6. Change the resistance of R10 to 22K, and repeat step 2, 3, 4, and 5

97

Differentiator Circuit Experiment

Experiment Steps:

1. Arrange the circuit as shown above. Use 10K and 100K for R11 and

R12 respectively, 100nF for C1 and Power Supply of +/-15V.

2. Adjust the signal generator to produce a square wave with V=3 Vp-p

and a frequency of 10 Hz.

3. Observe the input and output wave on oscilloscope.

4. Repeat step 2 and 3 for a frequency of 14kHz.

5. Repeat step 2, 3, and 4 for triangle and sinusoidal wave.

6. Change the resistance of R11 to 22K, and repeat step 2, 3, 4, dan 5.

98

5. References

Alexander, Charles K., Sadiku, Matthew N.O. (2009). Fundamental of

Electric Circuit (Fourth Edition). New York: McGraw-Hill.

www.electronics-tutorials.ws/opamp/opamp_1.html

http://hyperphysics.phy-

astr.gsu.edu/hbase/electronic/opampi.html#c2

http://www.ee.nmt.edu/~rhb/spr05-ee212/lab/lab0

99

Module VIII

Active Filter


Students should be able to understand function and use of a filter.

Students should be able to understand characteristics of a filter.

Students should be able to create an active filter with the desired

characteristics.


Basic Understanding of Electronic Filter

Understanding of Ideal Filter

Types of Filter based on the component

Types of Filter based on the passed frequency

General Working Principle of Filter

3. Basic Theory

3.1. Introduction

An RC active filter is a frequency separator circuit in which its

passive components comprises of resistor (R), capacitor (C), and

Op-Amp as the active component. The absence of inductor is

considered as an advantage mainly in the fabrication with the

integrated circuit. There are four types of filter that have ideal

frequency response as shown in figure 1 below:

100

The corresponding ideal filter frequency responses are of the

following types:

Low Pass, filter output (possibly considered as amplifier),

represented by H(j2f) appears for low frequencies, in the figure

it is shown from zero frequency until upper limit frequency fH.

Band Pass, filter output represented by H(j2f) appears for

frequencies between the lower limit frequency f1 and the upper

limit frequency f2.

High Pass, filter output represented by H(j2f) appears for

frequencies between the lower limit frequency f1 and the upper

limit frequency infinity (∞).

101

Band Rejection, filter output represented by H(j2f) does not

appear for frequencies between the lower limit frequency f1 and

the upper limit frequency f2.

In reality, frequency response of a filter is not as ideal as

shown in figure 1. H(j2f) response is not fixed in value, it varies

between maximum value of H0 and H1. The difference between

H0 and H1 is called ripple. For more detail, the real

characteristics of a low pass filter is shown on the following

figure.

If observed from the transfer function equation of an active

filter, it can be classified as follow:

102

1. Butterworth Filter, a filter in which the output could reduce

attenuation, along with the increasing of the order of that

corresponding filter.

2 Chebyshev Filter, a filter in which the output could reduce

ripple, along with the increasing of the order of that


3. Bassel Filter, a filter in which the output could reduce phase

difference, along with the increasing of the order of that


If observed from the configuration or topology of an active

filter circuit, it can be classified into two topologies:

1. Sallen Key Filter, an active filter that is used for even order (n

= 2, 4, 6, 8, …), so that it could directly result order 2 or its

multiple, and could save the use of other components.

2. Multiple Feedback Filter, an active filter that is used for even

order (n = 2, 4, 6, 8, …). This configuration is basically an

inverting amplifier, so that its resulted phase has 180o difference

than its original phase source.

103

Derivation of Sallen-Key Architecture for Active Filter

Kirchoff Current Law on node Vf:

𝑉𝑓 (1

𝑍1+

1

𝑍2+

1

𝑍4) = 𝑉𝑖 (

1

𝑍1) + 𝑉𝑝 (

1

𝑍2) + 𝑉𝑜 (

1

𝑍4)

Kirchoff Current Law on node Vp:

𝑉𝑝 (1

𝑍2+

1

𝑍3) = 𝑉𝑓 (

1

𝑍2) → 𝑉𝑓 = 𝑉𝑝 (1 +

𝑍2

𝑍3)

Substitute the KCL Vf equation into KCL Vp equation:

𝑉𝑝

= 𝑉𝑖 (𝑍2𝑍3𝑍4

𝑍2𝑍3𝑍4 + 𝑍1𝑍2𝑍4 + 𝑍1𝑍2𝑍3 + 𝑍2𝑍2𝑍4 + 𝑍2𝑍2𝑍1)

+ 𝑉𝑜 (𝑍1𝑍2𝑍3

𝑍2𝑍3𝑍4 + 𝑍1𝑍2𝑍4 + 𝑍1𝑍2𝑍3 + 𝑍2𝑍2𝑍2𝑍4 + 𝑍2𝑍2𝑍1)

Kirchoff Current Law on node Vn:

𝑉𝑛 (1

𝑅3+

1

𝑅4) = 𝑉𝑜 (

1

𝑅4) → 𝑉𝑛 = 𝑉𝑜 (

𝑅3

𝑅3 + 𝑅4)

104

Gain-Block Diagram

In accordance with the equation Vp = Vi*c + Vo*d. Gain Block

Diagram representation is made with a value of c and d as follow:

𝑐

= 𝑍2 ∗ 𝑍3 ∗ 𝑍4

𝑍2 ∗ 𝑍3 ∗ 𝑍4 + 𝑍1 ∗ 𝑍2 ∗ 𝑍4 + 𝑍1 ∗ 𝑍2 ∗ 𝑍3 + 𝑍2 ∗ 𝑍2 ∗ 𝑍4 + 𝑍2 ∗ 𝑍2 ∗ 𝑍1

𝑑

= 𝑍1 ∗ 𝑍2 ∗ 𝑍3

𝑍2 ∗ 𝑍3 ∗ 𝑍4 + 𝑍1 ∗ 𝑍2 ∗ 𝑍4 + 𝑍1 ∗ 𝑍2 ∗ 𝑍3 + 𝑍2 ∗ 𝑍2 ∗ 𝑍4 + 𝑍2 ∗ 𝑍2 ∗ 𝑍1

In accordance with the equation Vn, the value of b is obtained as

follows:

𝑏 =𝑅3

𝑅3 + 𝑅4

and a(f) is open-loop gain value of the amplifier.

𝑉𝑜

𝑉𝑖= (

𝑐

𝑏) (

1

1 +1

𝑎(𝑓)𝑏−

𝑑𝑏

)

105

Ideal Transfer Function

Open loop gain from an amplifier is very large, so that:

1

𝑎(𝑓)𝑏≅ 0

Creates a transfer function based on the gain block diagram as

shown below:

𝑉𝑜

𝑉𝑖=

𝑐

𝑏(

1

1 −𝑑𝑏

)

By inserting the value of 1/b = K, general transfer function of a

filter is obtained by using the Sallen Key architecture as follows:

𝑉𝑜

𝑉𝑖=

𝐾

𝑍1𝑍2𝑍3𝑍4 +

𝑍1𝑍3 +

𝑍2𝑍3 +

𝑍1(1 − 𝐾)𝑍4 + 1

High Pass Filter Transfer Function and Cutoff Frequency

Using formula derivation of the above ideal filter transfer

function, we can produce a transfer function for high pass filter

with unity gain as follows:

𝑉𝑜

𝑉𝑖=

1

1𝑠2(𝑅1𝑅2𝐶1𝐶2)

+1

𝑠(𝑅2𝐶1)+

1𝑠(𝑅2𝐶2)

+ 1

𝑓𝑐 =1

2𝜋√𝑅1𝑅2𝐶1𝐶2

106

Low Pass Filter Transfer Function and Cutoff Frequency

Using formula derivation of the above ideal filter transfer

function, we can produce a transfer function for low pass filter

with unity gain as follows:

𝑉𝑜

𝑉𝑖=

1

𝑠2(𝑅1𝑅2𝐶1𝐶2) + 𝑠(𝑅1𝐶2 + 𝑅2𝐶2) + 1

𝑓𝑐 =1

2𝜋√𝑅1𝑅2𝐶1𝐶2

4. Practicum

Low Pass Filter

o Tools and Equipments

Function generator

Oscilloscope

Protoboard and Jumper Cables

DC power supply

Components:

Resistor: 220Ω/1W (2); 100Ω/2W (1); 100kΩ/0,5W

(1)

Capacitor: 0,1μF/400V (2)

Op Amp (1)

107

o Experiment Circuit

o Experiment Steps

1. Arrange the circuit as shown in the figure.

2. Attach the function generator with sinusoidal wave mode on

the input channel and oscillator on the output channel.

3. Give power supply to the circuit, record the voltage level and

the frequency indicated by the oscilloscope for different input

frequencies.

Band Pass Filter


Function generator

Oscilloscope


DC power supply

Components:

Resistor: 2.2kΩ/0.5W (1); 4.7kΩ/0.5W (2);

6.8kΩ/0.5W (1);

108

Capacitor: 4.7nF/200V (1); 470nF/200V (1);

330nF/200V (1); 2.2nF/200V (1);

TL-072 (2)


o Experiment Steps


2. Attach the function generator with sinusoidal wave mode on

the input channel and oscillator on the output channel.

3. Give power supply to the circuit, record the voltage level and

the frequency indicated by the oscilloscope for different input

frequencies.

High Pass Filter


Function generator

Oscilloscope

Protoboard and Jumper cables

109

DC power supply

Components:

Resistor: 220Ω/1W (2); 100Ω/2W (1);

100kΩ/0,5W (1)

Capacitor: 0,1μF/400V (2)

Op Amp (1)


o Experiment Steps


2. Attach the function generator with sinusoidal wave

mode on the input channel and oscillator on the output

channel.

3. Give power supply to the circuit, record the voltage level

and the frequency indicated by the oscilloscope for

different input frequencies.

110

Band Reject Filter


Function generator

Oscilloscope


DC power supply

Components:

Resistor: 2.2kΩ/0.5W (1); 4.7kΩ/0.5W (2);

6.8kΩ/0.5W (1);

Capacitor: 4.7nF/200V (1); 470nF/200V (1);

330nF/200V (1); 2.2nF/200V (1);

TL-072 (2).


111

o Experiment Steps

1. Arrange the High Pass and Low Pass circuit in series

connection.

2. Attach the function generator with sinusoidal wave mode

on the input channel and oscillator on the output

channel.

3. Give power supply to the circuit, record the voltage level

and the frequency indicated by the oscilloscope for

different input frequencies.

5. References

Sutanto, Rangkaian Elektronika Analog dan Terpadu.

Millman, Jacob & Arvin Grabel, Microelectronics.

Millman, Jacob & Christos Halkias, Integrated Electronics.

112

Module IX

Application


Understand the working principle of light sensor circuit as an

automatic switch for 220 VAC lamp.

Understand the working principle of discrete multivibrator

circuit and IC.

Understand the working principle of motor driver for DC motor

by using MOSFET.


Working principle of LDR sensor and Voltage Divider principle

Comparator and switch using Op-Amp and BJT.

Relay as AC switch using DC control.

Discrete vibrator with transistor, capacitor, and resistor

Vibrator IC 555

Motor driver H-Bridge with MOSFET and optocoupler

113

3. Basic Theory

3.1 Light Sensor as Automatic Switch for 220V Lamp

This circuit is a circuit that can turn on and off lamp

automatically based on the light intensity that touches the

sensor. This circuit uses the LDR (light dependent resistor)

to calculate the light intensity that is converted into

electrical resistance. The more light intensity touches the

sensor, the less resistance sensor value will be. The circuit

schematic can be seen on figure 9 below:

Figure 9

There are 3 stages on the above schematic; sensor stage,

comparator stage and switch stage. Each stage explanation

is shown below.

114

a. Sensor stage

This stage consists of LDR and a variable resistor (widely

known as potentiometer) that is connected with the voltage

source. Both has resistive nature and is used as voltage

divider from the voltage source value. Basically, the usage of

potentiometer can be replaced by using fixed resistor.

However, the user does not have the ability to set when the

light is on or off in accordance to the intensity of light falls

on the sensor. With combination of both resistors, the

voltage value on the potentiometer is used as input for

comparator stage. In this module, the voltage on

potentiometer becomes the comparator inverting input.

When the light intensity is high, the voltage value on

potentiometer will be close to Vcc, while the potentiometer

voltage value will be close to 0 V when the light intensity is

low.

b. Comparator Stage

This stage has a function for interpreting the value of

LDR sensor reading. This stage consists of a pair of fixed

resistor acting as voltage divider and Op-amp acting as

comparator, and both are directly connected with the

voltage source. By determining the limit of voltage value

wanted by the user, the comparator could interpret the light

intensity captured by the LDR sensor. This voltage value

limit is specified by the fixed resistor pair that is connected

115

with the non-inverting input of Op-amp. Thus, the non-

inverting input acts as a reference voltage. When the light

intensity is high, the non-inverting voltage value is less than

that of the inverting voltage value, and vice versa. As a

result, the high and the low light intensity is interpreted as 0

& 1 logic sequentially.

c. Switch Stage

This stage consists of NPN BJT acting as switch and relay

acting as switch on lamp circuit. When the light intensity is

high, the relay is in the state of normally open, and vice

versa. This condition is regulated by the NPN BJT that

obtains the input from the comparator output. The coil part

of the relay is connected to the NPN BJT collector. When the

light intensity is high, logic 0 becomes the NPN BJT input,

causing no current flow at the base putting the BJT in cut-off

mode. No base current results in the absence of collector

current, creating no current flow through the relay coil and

no magnetic field to pull the metal relay switch is created.

The lamp is in off condition. When the light intensity is low,

logic 1 becomes the NPN BJT input, causing current flow at

the base and collector putting the BJT in the saturation

mode. The presence of collector current results in the

existence of current that passes through the relay coil, so

that magnetic field is created and is able to pull the metal

relay switch. The lamp is in on condition. Note that the lamp

must always be connected with the 220V source.

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3.2 Astable Multivibrator with Discrete Component

This circuit is an oscillator circuit whose function is to

generate periodic signal with square waveform, so that the

generated signal has values of logic 0 and 1. The resulted

periodic signal does not require a trigger to change the logic

0 into 1 and vice versa. Howevr, this circuit is designed in

order to freely oscillate the signal. Therefore, astable

multivibrator is also called as Free Running Multivibrator. It

is called multivibrator due to its 2 outputs which oscillates

with different phase.

This circuit has two identic stages in which each of them

consists of NPN BJT acting as switch, pair of capacitor and

resistor, and LED. The working principle of this circuit is

explained in the following:

a. This circuit analysis is initiated by assuming which BJT

will be active and which one will not be active. For

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instance, initially assume that Q1 is the BJT that will be

active and Q2 is the one that will not be active.

b. To make Q1 active, the base current should flow from the

Vcc through R3, so that collector current flows through R1

and eventually to the emitter terminal. Due to the short

connection between the collector and emitter of Q1,

current will not flow through the blue LED which has

higher value of resistance.

c. Because Q2 is not active, the collector and emitter

terminals of Q2 are open. The current flowing through Q4

will directly heads to the yellow LED putting the LED in

the on condition. At the same time, the capacitor will

undergo charging due to flow of current on R3 and R4.

d. After the capacitor is fully charged, it will experience

discharging. When undergoing discharging, the base

current flows through R2 resulting in Q2 to be active and

current flows from the Q2 into the Q2 emitter. The yellow

LED is in off condition. By the same method, the blue LED

is on. This process keeps repeating sequentially.

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3.3 Astable Multivibrator with IC (Integrated Circuit)

LM555

The difference in this circuit with th previous one is in

the usage of IC LM555 as circuit that produces oscillated

signal. The IC LM555 is considered as one of the oldest IC

timer type and often used due to its simplicity. LM555

consists few stages in its circuit, that is, 3 resistors acting as

voltage divider, 2 comparators and RS flip-flow. It is shown

in the following an LM555 in astable mode:

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The above figure is a schematic circuit in an IC LM555.

The following shows how IC LM555 works:

a. Voltage divider divides the Vcc voltage into 3 equal values

in magnitude. Then, reference value with magnitude of

1/3 and 2/3 from the Vcc becomes the reference voltage

of the 2 comparators (1/3 of Vcc goes to the non-inverting

input of comparator 2, while 2/3 of Vcc goes to the

inverting input of comparator 1) that will give logic values

on RS Flip-flop gate. Comparator 1 & 2 will get into the

Reset and Set inputs on RS Flip-flop sequentially.

b. The external capacitor that is connected into pin 2 & 6 of

LM555 will be filled with charges due to Vcc through RA

and RB. In this condition, the voltage value is still below

1/3 of Vcc, resulting in comparator 2 to give logic 1 on the

Set input. By assuming that the previous flip-flop state is

of logic 0, the output of this Set input will give logic value

of 0 (see on RS Flip-flop schematic above) that will

eventually be a state for the Reset input. At the same time,

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the capacitor voltage value is still below 2/3 of Vcc,

resulting in comparator 1 to give logic 0 on the Reset

input. The output of this Reset input is logic 1 and will

become a state for the Set input as well as output of the IC

LM555.

c. Then the capacitor is filled in the range of 1/3 to 2/3 of

the Vcc value. In this condition, each of the comparator 1

& 2 will give logic value of 0 on the Reset & Set input.

Output of the Set input is logic 0 as well as becoming the

state for the Reset input. Whereas, the output of the

Reset input is logic 1 as well as becoming the state for the

Set input. It can be seen that in this range, the output of

IC LM555 is still having logic of 1.

d. When the capacitor is filled with more than 2/3 of Vcc

value, the comparator 1 & 2 will give logic value of 1 & 0

on the Reset & Set input sequentially. Output from thr Set

input is logic 0 as well as becoming the state for the Reset

input. Whereas, the output of Reset input is logic 0. In

this condition, the capacitor will undergo discharging

towards pin 7 through RB. It can be concluded that after

the capacitor is filled with more than 2/3 of the Vcc

value, the output of IC LM555 is in the off condition.

e. The cycle is then goes to the capacitor discharging in

which the analysis is done reversely (backwards). The

result of the analysis is shown in the following table.

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Charging

Stage V<(Vcc/3) (Vcc/3)<V<(2Vcc/3) (2Vcc/3)<V Comparator 1

(Reset) 0 0 1

Comparator 2 (Set)

1 0 0

Flip-flop (Q) 1 1 0

Discharging

Stage (2Vcc/3)<V (Vcc/3)<V<(2Vcc/3) V<(Vcc/3) Comparator 1

(Reset) 1 0 0 Comparator 2

(Set) 0 0 1 Flip-flop (Q) 0 0 1

3.4 Motor Driver with Optocoupler

This circuit functions as a motor driver so that it rotates

in 2 directions; either clockwise or counter-clockwise. This

circuit comprises of a P-MOSFET pair (2 top MOSFETs, Q1

AND Q2), an N-MOSFET pair (2 bottom MOSFETs, Q3 and

Q4), a pair of optocoupler and a stage of motor speed

controller. In principle, motor rotates in accordance with

the direction of current that flows into the motor coil due to

the presence of electromagnetic field, resulting in the circuit

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creation based on the principle of how to direct current in 2

different directions on the motor.

Keep in mind that P-MOSFET will make current flow

from Drain to Source if the Gate is given negative voltage

and vice versa for the N-MOSFET. From the above figure, it

is clearly seen that there are 2 logic inputs, that is, the

optocoupler input. Optocoupler is an IC that functions as

isolator between the input and the output. Inside it, there is

a device which produces infrared light and NPN BJT. The

infrared has a function to produce base current so that the

NPN BJT will be active.

The analysis is shown as follows:

a. Assume that the left and right optocoupler as O1 and O2.

When both optocoupler is not given any input, then the

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BJT will be in the off state. This results in the 2 gates, Q1

and Q3 for instance, to be connected in parallel and has a

value equal to that of the Vcc. The same thing also occurs

on Q2 and Q4. In this condition, Q1 and Q2 are in the off

condition, whereas, Q3 and Q4 are in the on/active

condition. However, due to Q1 and Q2 being in the off

mode, there are no current that flows from Q3 and Q4

Drains. Moreover, the non-active state of Q1 and Q2

results in voltage value on both motor terminals to have

0V. Therefore, the motor will not rotate if the logic input

is 00.

b. When the two optocouplers are given logic input of 1. In

this condition, both BJTs are in the active condition. The

Gate that is connected in parallel has a value of 0V

because it is also connected in parallel with the collector-

emtter terminal of the BJT that is in short-circuited. This

results in Q1 and Q2 to be in the active condition, while

Q3 and Q4 to be in the off condition. The Q1 and Q2 Drain

are shortly connected with each of its Source, so that the

value of the voltage on every motor terminal is equal to

Vcc value. Due to the off state of Q3 and Q4, each Drain

and Source are open. Thus, the motor will not rotate if the

logic input is 11.

c. However, if it is given logic 1 on O1 and logic 0 on O2, the

BJT O1 is in the active state, while BJT O2 is in the off

state. This results in the Gate voltage Q1 and Q3 to be 0V,

while the Gate voltage Q2 and Q4 to be equals Vcc. In this

condition, Q1 and Q4 are in active condition, while Q3 and

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Q3 are in the off condition. Therefore, the voltage on the

left and right terminal are equal to Vcc and 0V

sequentially. This results in current flow from the left

terminal into the right terminal towards the ground and

the motor rotates clockwise.

d. Next, if it is given logic 0 and 1 on O1 and O2 sequentially,

then the BJT O1 is in the off state, while BJT O2 is in th

active state. This causes the Gate voltage Q1 and Q3 to be

equal to the Vcc, while Gate voltage Q2 and Q4 to be equal

to 0V. In this condition, Q1 and Q4 are in the off state,

while Q2 and Q3 are in the active state. Therefore, the

voltage on the left and right terminal of the motor are 0V

& Vcc sequentially. This causes current to flow from the

right terminal to the left terminal towards the ground and

the motor rotates counter-clockwise.

e. The speed can be variably controlled by giving PWM

(pulse width modulation) input on the control stage of the

motor speed. Principally, the way how it works is similar

to that of optocoupler and MOSFET explained above, and

the input oscillates with respect to the time duration of

high and low that can be varied, so that the motor speed

can be variably controlled.

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4. References

Modul Praktikum Rangkaian Elektronika untuk mahasiswa

Teknik Elektro tahun 2016.

Boylestad, Robert L., Nashelsky, Louis. 2013. ELECTRONIC

DEVICES & CIRCUIT THEORY, Eleventh Edition. United States :

Pearson.

Flip-flop (Electronics). Diakses dari

https://en.wikipedia.org/wiki/Flip-flop_(electronics) pada 5

Februari 2017.

41 LED Flasher using 555 IC. Diakses dari

http://www.instructables.com/id/41-LED-Flasher-Circuit-

using-555-IC/step2/Build-the-circuit/ pada 5 Februari 2017.

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Module X

Final Project

*Provision regarding the Final Project will be informed further.

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