Electronic Circuits and Devices: A Comprehensive Report

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Electronic
Circuits and
Devices
1

Table of Contents
Introduction......................................................................................................................................5
LO1. Determine the operational characteristics of amplifier circuits..............................................6
Task 1...........................................................................................................................................6
1.1 Describe briefly the operational characteristics of Power amplifiers: class A, B and AB.
State one application of each of the amplifier.............................................................................6
1.2 List the different performance characteristics of Class A, B and AB amplifiers................10
1.3 Refer to the amplifier in Fig 1.0. The amplifier has a mid-band gain of 10 and a frequency
range of 159.0 Hz to 14.5 KHz. Apply practical tests on the amplifier’s performance and
comment on the results..............................................................................................................14
1.4 Evaluate the validity of the simulation and practical results for the operational amplifier
circuits against the designed criteria and identify the sources of errors....................................16
LO2: Investigate the types and effects of feedback on an amplifier’s performance.....................19
Task 2.............................................................................................................................................19
2.1. Discuss briefly the types of feedback and their effect on the amplifier’s performance.....19
2.2 Describe the effect of negative feedback on the CE amplifier in Fig 2.0............................21
2.3 Perform practical tests to analyze the effect of applying feedback on the CE amplifier in
Fig .............................................................................................................................................22
2.4 Plot the gain/frequency response of the CE amplifier with and without feedback using
Multisim and evaluate the results of practical and simulation tests to analyze the effect of
feedback on the amplifier’s performance..................................................................................24
LO3: Examine the operation and application of oscillators..........................................................27
Task 3...........................................................................................................................................27
3.1 List the main types of oscillators and their applications......................................................27
3.2 Assess the performance of the oscillators in Fig 3a & 3b...................................................28
Wein Bridge Oscillator..............................................................................................................28
3.3 Simulate the circuits in Fig 3.0 a & 3b and analyze the results obtained from practical and
simulation results.......................................................................................................................30
4.1 You are required to identify the appropriate manufacturer’s data sheet for the following
devices and circuits:...................................................................................................................34
4.2 Interpret the relevant information from the manufacturer’s data sheet when using the above
devices in 4.1.............................................................................................................................38
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4.3 Perform tests on the above devices and circuits and recommend appropriate action..........41
4.4 Use Multisim to test the above devices and circuits and analyze and compare both the
virtual and practical results........................................................................................................50
Conclusion:....................................................................................................................................58
References:....................................................................................................................................59
List Of Figures
Figure 1: Class A Amplifier............................................................................................................8
Figure 2: Class B Amplifier.............................................................................................................9
Figure 3: Class AB Amplifier........................................................................................................10
Figure 4: Output of Class A Amplifiers........................................................................................11
Figure 5: Position Of Q-Point for Class A.....................................................................................12
Figure 6: Output of Class B Amplifiers.........................................................................................12
Figure 7: Position Of Q-Point for Class B.....................................................................................13
Figure 8: Position of Q-Point For Class ab....................................................................................13
Figure 9: Efficiency Comparison...................................................................................................14
Figure 10: Amplifier Circuit..........................................................................................................15
Figure 11: Fourier Analysis...........................................................................................................16
Figure 12: AC Analysis.................................................................................................................16
Figure 13: Phase v/s Frequency.....................................................................................................16
Figure 14: Amplifier Circuit Diagram...........................................................................................17
Figure 15: Oscilloscope results......................................................................................................18
Figure 16:Input & Output waves...................................................................................................19
Figure 17: Input & Output Waves.................................................................................................19
Figure 18: CE Amplifier................................................................................................................23
Figure 19: Simulation Result.........................................................................................................24
Figure 20: CE Amplifier................................................................................................................25
Figure 21: AC Analysis.................................................................................................................25
Figure 22: Phase v/s Frequency.....................................................................................................26
Figure 23: CE Amplifier without Feedback..................................................................................26
Figure 24: AC Analysis.................................................................................................................27
Figure 25: Phase v/s Frequency.....................................................................................................27
Figure 26: Output of Wein Bridge Oscillator................................................................................29
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Figure 27: Output Signal...............................................................................................................30
Figure 28: Colliptis oscillators Ideal Output Diagram..................................................................31
Figure 29: colliptis oscillators output Diagram.............................................................................31
Figure 30: Circuit of Wein Bridge Oscillator................................................................................32
Figure 31: Result of Simulation.....................................................................................................33
Figure 32: Circuit of colliptis oscillators.......................................................................................34
Figure 33: Output Diagram of Colliptis Oscillator........................................................................35
Figure 34: Circuit of Diode............................................................................................................43
Figure 35: Input Diagram..............................................................................................................43
Figure 36: Output Signal...............................................................................................................44
Figure 37: Circuit Of Transistor....................................................................................................44
Figure 38: CIRCUIT OF TRANSISTOR......................................................................................45
Figure 39:Circuit of Operational Amplifier...................................................................................46
Figure 40:INPUT & OUTPUT SIGNAL......................................................................................47
Figure 41: Circuit & Output of Power Supply...............................................................................48
Figure 42: Transistor Amplifier Circuit- 2N3904.........................................................................49
Figure 43: Ideal Output Diagram...................................................................................................50
Figure 44: After Test Output Diagram..........................................................................................51
Figure 45: Diode Circuit................................................................................................................51
Figure 46: Volage v/s Time Graph................................................................................................52
Figure 47: Transistor Circuit.........................................................................................................52
Figure 48: TRANSISTOR CIRCUIT............................................................................................53
Figure 49: Operational Amplifier Circuit......................................................................................54
Figure 50: Voltage V/S TIME Graph............................................................................................55
Figure 51: Circuit of Power Supply...............................................................................................55
Figure 52: Output of Power Supply...............................................................................................56
Figure 53: Circuit of Transistor.....................................................................................................57
Figure 54: Output of Transistor.....................................................................................................58
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List of Tables
Table 1: Various Oscillators & Their Applications.......................................................................28
Table 2: Maximum Ratings of Diode 1N4007..............................................................................35
Table 3: Maximum Ratings of transistor.......................................................................................36
Table 4: Maximum RATINGS OF Operational Amplifier 741....................................................37
Table 5: Maximum Ratings of P.S. 3N248...................................................................................37
Table 6: Maximum Ratings of T.A.Circuit - 2N3904..................................................................38
Table 7: Electrical Characteristics of Diode..................................................................................39
Table 8: Electrical Characteristics of Transistor...........................................................................39
Table 9: ELECTRICAL CHARACTERISTICS OF TRANSISTOR...........................................40
Table 10: ELECTRICAL CHARACTERISTICS OF Amplifier..................................................41
Table 11:ELECTRICAL CHARACTERISTICS OF Power Suply- 3N248.................................41
Table 12: Electrical Characteristics of Transistor Amplifier Circuit- 2N3904.............................42
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Introduction
The company holds a long-time experience in the designing and testing of the electronic circuits
with the use of analogue devices. For further increasing the available information and retaining
the available information in a better way this report is been submitted. The report covers the
various characteristics like the operational and the performance of the amplifier’s circuits. The
feedback’s types, their effect on the amplifiers and a special case of negative feedback is
discussed. A brief description regarding the oscillators and their performance is done and the
supporting results from the tasks are also provided. In the end, a manufacturer’s data sheet is
provided for the various devices and the circuits they are used in including some tests and the
resulting action which should be taken on them as well.
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LO1. Determine the operational characteristics of amplifier circuits.
Task 1
1.1 Describe briefly the operational characteristics of Power amplifiers: class
A, B and AB. State one application of each of the amplifier.
Amplifiers
There are various electronic devices performing various functions in day to day life of a person,
one of these electronic devices is the amplifier. The amplifier helps in amplifying the signal in
various ways. The amplifier could be used to increase the voltage, power, or current of a signal
(Perreault,2018).
It is easier to understand amplifiers if they are briefly classified, the four major types of
amplifiers are listed below (LI, 2017).
(i) Class A
(ii) Class B
(iii) Class AB
Power Amplifiers & their operational characteristics
(i) Class A
The amplifier operating in class A has the design of basic circuit in such a way that the point
of operation lies in the center of the load line of the AC.
Operational Characteristics of the Class A amplifier:
 The amplifier is good in preserving the signal and only a less amount of signal is
distorted.
 The circuit is designed in a very simple way keeping in mind that the operating point
should lie in the center of the load line.
 The amplifier is stable as compared to the other amplifiers.
 The amplifier has a down point too, cause the amplifier to generate high heat during
output.
 The amplifier is the best in linearity out of all other types due to its simple design.
 One of the benefits of using Class A type is that there is no charge storage problem.
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FIGURE 1: CLASS A AMPLIFIER
(Source: Elprocus,2015)
(ii) Class B
Another important type of amplifier is the class B amplifier in which the operating point of
the amplifier is designed in such a way that the flow of current is only during the positive
half cycle of the input signal.
Major characteristics of this type of amplifier are as follows:
 The amplifier is stable in nature and doesn’t shows many fluctuations in the circuit
and hence becomes reliable.
 The amplifier requires 2 complementary transistors and use them each during the
negative and the positive cycle.
 The amplifier requires less head output than others.
 Even with all the shortcomings the amplifier still has higher efficiency.
Application of the amplifier
The amplifier is majorly used in making a low-cost design.
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FIGURE 2: CLASS B AMPLIFIER
(Source: Gupta, 2018)
(iii) Class AB:
In these kinds of amplifiers, the design is made in such a way that the operating point should
lie near the cut-off voltage. The input circuit is reversed biased and hence there would be no
collector current (Li, 2017).
 The major characteristics of the Class AB amplifiers:
 These types of amplifiers are efficient enough to be used during various operations.
 The transistors used in this type of amplifiers work together as there are two
transistors used in this amplifier.
 The amplifier comprises of both types of the characteristics from the Class A and
Class B.
Application of the amplifier
These types of amplifiers are generally used in the hi-fi systems.
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FIGURE 3: CLASS AB AMPLIFIER
(Source: Gupta, 2018)
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1.2 List the different performance characteristics of Class A, B and AB
amplifiers.
The performance characteristics of the amplifiers are the outcomes of there operational
characteristics. As the operational characteristics are varying with the type of the amplifiers, then
so will be the performance characteristics. There are various parameters to judge the
performance of the amplifiers but to simplify the process a little the certain parameters like the
Gain in the voltage, output of the amplifier or the maximum output are chosen. Using these the
amplifier’s performance characteristics can be easily justified.
Class A amplifiers:
This type of power amplifiers are the ones which allow the collector current to flow for the
whole life cycle of the input signal. The design for this amplifier is very basic and the motive for
that is to keep the operating point comes between the AC load line. It amplifies the small signals
without the distortion of the signal and also with just a negligible breakage.
As shown in the figure the transformer is present at the collector like a load.
 For class A amplifier the output conducts for 3600 cycles.
 The Q-point is set at the middle of the load line so that AC signal can swing for a full
cycle.
FIGURE 4: OUTPUT OF CLASS A AMPLIFIERS
(Source: Krystelle, 2012)
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FIGURE 5: POSITION OF Q-POINT FOR CLASS A
(Source: Krystelle, 2012)
Class-B Amplifiers
The amplifiers created with the use of two active devices which conduct ½ of the actual cycle.
The devices in this circuit got active only for the half of the cycle, this results in an improved
efficiency up to 25-30% from class A amplifier, ideally, it provides more than 60% efficiency.
The Efficiency of the class B amplifier cannot be increased by more than 78%.
Heat dissipation is low in this type of class as a low heat sink space is provided in this type.
The class B amplifier’s output happens for 1800 or ½ of the AC input signal.
Q-Point for this lies at 0V on load line, it means that the AC signal is able to swing for the one-
half cycle.
FIGURE 6: OUTPUT OF CLASS B AMPLIFIERS
(Source: Krystelle, 2012)
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