Electronic Circuit and Devices: Unit 22 Practical Assignment

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UNIT 22 - ELECTRONIC CIRCUIT
AND DEVICES

Contents
Introduction:...............................................................................................................................3
LO1............................................................................................................................................4
P1............................................................................................................................................4
P2............................................................................................................................................7
M1..........................................................................................................................................9
LO2..........................................................................................................................................12
P3..........................................................................................................................................12
P4..........................................................................................................................................16
M2........................................................................................................................................17
LO3..........................................................................................................................................22
P5..........................................................................................................................................22
M3........................................................................................................................................25
LO4..........................................................................................................................................30
P6..........................................................................................................................................30
P7..........................................................................................................................................33
M4........................................................................................................................................40
References:...............................................................................................................................47

List of images:
Figure 1: Class A Amplifier.......................................................................................................5
Figure 2: Class B Amplifier.......................................................................................................6
Figure 3: Class AB Amplifier....................................................................................................7
Figure 4: Performance Summary...............................................................................................8
Figure 5: Amplifier..................................................................................................................10
Figure 6: Graphs.......................................................................................................................10
Figure 7: Amplifier..................................................................................................................11
Figure 8: Feedback amplifier...................................................................................................13
Figure 9: Positive Feedback Amplifier....................................................................................14
Figure 10: Negative Feedback Amplifier.................................................................................14
Figure 11: Feedback Amplifiers Topologies............................................................................15
Figure 12: With Feedback........................................................................................................18
Figure 13: Oscilloscope – XSC1..............................................................................................19
Figure 14: Result with Feedback..............................................................................................19
Figure 15: CE Amplifier with feedback...................................................................................20
Figure 16: Without Feedback...................................................................................................20
Figure 17: Result without feedback.........................................................................................21
Figure 18: CE Amplifier without feedback..............................................................................21
Figure 19: Oscilloscope – XSC1..............................................................................................22
Figure 20: Oscillator................................................................................................................23
Figure 21: Armstrong Oscillator..............................................................................................24
Figure 22: Hartley Oscillator...................................................................................................24
Figure 23: Colpitts Oscillator...................................................................................................25
Figure 24: Wien Bridge............................................................................................................26
Figure 25: Colpitts Oscillator...................................................................................................27
Figure 26: Resultant Wien Bridge............................................................................................28
Figure 27: Exponentially Increase Resultant Graph................................................................28
Figure 28: Colpitts Oscillator...................................................................................................29
Figure 29: Oscilloscope – XSC1..............................................................................................29
Figure 30: Sawtooth Resultant Graph......................................................................................30
Figure 31: Diode......................................................................................................................31
Figure 32: Transistors..............................................................................................................31
Figure 33" Operational Amplifier............................................................................................32
Figure 34: Power Supply Circuit..............................................................................................33
Figure 35: Two Transistor Amplifier Circuit...........................................................................33
Figure 36: Diode......................................................................................................................41
Figure 37: Resultant Graph......................................................................................................42
Figure 38: Transistor................................................................................................................43
Figure 39: Resultant Graph......................................................................................................43
Figure 40: Operational Amplifier.............................................................................................44
Figure 41: Resultant Graph......................................................................................................45
Figure 42: Transistor Amplifier circuit....................................................................................45
Figure 43: Resultant Graph......................................................................................................46
Figure 44: Power Supply..........................................................................................................47

Introduction:
Electronics circuits and devices are the area of electronics that used to perform different
operations with using its components as, diodes, triodes, power suppliers, rectification and
other instruments. The current assignment is about the enhance the skills and knowledge
about the area of electronics with performing some practical and simulation tests. In the role
of a technical in an electronics laboratory, perform some task about the amplifiers, different
types of feedback and track the performance of the amplifier. The third task will include the
types of oscillators and its applications that used to increase the performance of the
oscillators. Different kinds of circuits are available to perform the practical tasks as well as
explain some other terms like diodes, transistors, operational amplifiers and many more.

LO1 Determine the operational characteristic of amplifier circuits
P1 Describe the types of amplifiers available and their applications
Amplifiers are used to boost or increase the electronics current as of the electronic and
electromagnetic component. It is also known as “amp”. An amplifier has basically two types,
pre and power. The pre type of amp is used in small audio devices like a CD player, network
streamers or turntables. On the other side, power amplifiers are used in the loudspeakers. All
the amplifiers are not the same as these are different from each other because of their
different operating and construction characteristics. Amplifiers divide in the form of classes
like A, B, AB, C, D and others (Rouse, 2005). Here following are some of the amplifiers
classes with their application as follows:
Class A:
Class A types of amplifiers have the most common topology because there is only one
switching transistor for the output in the amplifier design. Due to its high gain and the low
signal distortion level, it is considered one of the best class in terms of the amplifier design. It
has the best sounding among all the amplifier classes.
Figure 1: Class A Amplifier
Source: (electronics-tutorials, 2019)
Applications:
 Class A amplifier used in high-fidelity audio amplifier designs.

 Class A amplifier has improved high-frequency response because there is no time is
needed in order to turn on the device due to the full time ON status of the active
device.
 The configuration of the single-ended can be practically and easily realized in it.
 Class A amplifier also has no crossover distortion.
Class B
It is introduced for the solution to the heating problems and the efficiency of the class A
amplifier. It overcomes these problems by using the two complementary transistors. There is
no current of DC base bias. The DC power is small because the quiescent current is zero in
this amplifier.
Figure 2: Class B Amplifier
Source: (electronics-tutorials, 2019)
Applications:
 It removes the even harmonic by using the push-pull system in the class B amplifier.
 Eliminating the even harmonic enables the circuit to give more output per device
(Electronics-notes, 2019).
Class AB
This type of amplifier is the combination of class A and B amplifier and currently most used
amplifier with the powerful audio design amplifier. The property of the class A and B
amplifier are included in the class AB amplifier topology. During the configuration of the AB

amplifier, the efficiency of the amplifier reduces but individually the efficiency remains same
of both amplifier A and B.
Application:
 This kind of amplifier has two output transistors that conduct somewhere between the
angles of 180 degrees to 360 degrees in the input waveform.
 This is the amplifier of the power category for which distortion is worst on the low
signal and it is lowest when the signal reaches the clipping point.
Figure 3: Class AB Amplifier
Source: (electronics-tutorials, 2019)

P2 Examine the different performance characteristics of types of amplifier
Amplifiers basically have three main classes, A, B and AB amplifiers that have different
characteristics as:
Figure 4: Performance Summary
(Electronics-notes, 2019)
The performance of the different amplifiers is different as per their circuit diagram and output
waveforms. The operating mode of the amplifiers depends on their circuit and conduction
angle as the conduction angle of class A is equal to 360 degree and for class, B is equal to
180 degree and for class AB less than equal to 180 degrees. Some other factors of the three
amplifiers that are different from each other as:
Factors Class A Class B Class C
Efficiency The max. resistive
load efficiency is
25% and max. load
collector efficiency
is 50% and both are
50%.
The average current
of class B is less
then class A, as well
as power
dissipation, is also
less. The class B
theoretical
efficiency is 78.5.
The efficiency
depends on the
conduction angle as
at the angle of 180
the efficiency is
78% and it
decreases as the
efficiency increases.
Max. Peak voltage MPP < Vcc MPP = Vcc MPP = 2(Vcc)
Linearity and
distortion
Low distortion with
high linearity
Low linearity with
small distortion
Poor linearity with
high distortion
Uses Amplifier with low
power
Power amplifier
with the output
High distortion so
cannot use an

amplifier
(Gundaniya, 2015)

M1 Explain the results obtained from applying practical tests on an amplifier’s
performance
Figure 5: Amplifier
After checking the above image, create the graph with a gain of 10 and within the frequency
range of 159.0 Hz to 14.5 kHz. Conduct the AC analysis with creating the first graph on the
gain of 10 and a second graph within the range of 159.0 Hz to 14.5 kHz. The frequency break
at the point 1.00000K to create the second graph.
Figure 6: Graphs
Apply the practical test and create the amplifier with checking its performance in the below
image.

Figure 7: Amplifier