Module Name: Linear Electronics
Level: 5
Credit Rating: 10
Weighting: 15%
Issue Date: Nov. 3rd 2015
Hand-in Date: Jan. 11th 2016
Feedback: Feedback will be given when your coursework is returned to you within two weeks. Feedback will be both written and verbal.
Programmes: BEng (Hons) Electrical and Electronics Engineering
Introduction
This coursework aims to strengthen your knowledge and understanding of linear electronic circuit design. In this coursework, you will need to complete an amplifier design by analysing one given incomplete circuit schematic. You first need to calculate the required values of certain components. Then you need to verify your design in the simulation environment. Finally, you are required to further improve the performance of the amplifier by adding extra circuits.
Learning Outcomes to be assessed
LO3 Use CAD tools for circuit design and simulation
This assignment will assess elements of the above learning outcome.
UK-SPEC Learning Outcomes
US2 Knowledge and understanding of mathematical principles necessary to underpin their education in
their engineering discipline and to enable them to apply mathematical methods, tools and notations proficiently in the analysis and solution of engineering problems
E1 Understanding of engineering principles and the ability to apply them to analyse key engineering processes.
E2 Ability to identify, classify and describe the performance of systems and components through the use of analytical methods and modelling techniques
E4 Understanding of and ability to apply a systems approach to engineering problems
D1 Investigate and define a problem and identify constraints including environmental and sustainability limitations, health and safety and risk assessment issues
D4 Use creativity to establish innovative solution
D5 Ensure fitness for purpose for all aspects of the problem including production, operation, maintenance and disposal
D6 Manage the design process and evaluate outcomes
S1 Knowledge and understanding of commercial and economic context of engineering processes
P2 Workshop and laboratory skills
P3 Understanding of contexts in which engineering knowledge can be applied (e.g. operations and management, technology development, etc.)
P4 Understanding use of technical literature and other information sources
P6 Understanding of appropriate codes of practice and industry standards
P7 Awareness of quality issues
P8 Ability to work with technical uncertainty
Coursework requirement
This coursework involves three parts: Design an amplifier through your calculation, verify your design with simulation tool, Proteus, and finally prepare a report.
Design an amplifier:
Fig. 1 A partially designed amplifier and transistor pin layout
A partially designed transistor amplifier is given in Fig. 1. You should complete the following tasks:
1. Using the suitable figures or diagrams, explain how the input small signal is amplified with the circuit given in Fig.1.
2. DC design without connecting RL
Determine the DC bias current in collector, Ic, to give the maximum peak-to-peak value for Vout without clipping (i.e the DC bias point should meet VCE= IC*(Rc//RL)). You may assume that Vbe=0.7 V and the base current is negligible.
Determine R1 to produce the required Ic.
Calculate the voltage drop of V(R1), V(R2), V(Rc), V(Re), Vce, and Vc.
3. Frequency Design
The critical frequency for the output coupling capacitor Co is required to be ≤ 10 k Hz, when there is no load (i.e. RL=∞). Determine the minimum value of Co.
4. AC Design
If the amplitude of Vout is required to be 2 V without clipping, determine:
(i) The minimum load, RL(min) can be applied to this amplifier.
(ii) The power delivered to this RL.
Verify the amplifier with simulation
1. Build the amplifier schematic in Proteus ISIS environment.
2. Measure the DC voltages and fill the following table
Voltage (V)
V(R1)
V(R2)
V(Rc)
V(Re)
Vbe=
Vce=
Vc=
Measure the current in the collector, Ic.
3. AC measurement with a load of RL = 1MΩ
(i) Set Vin=10 mV in amplitude at a frequency of 100 kHz.
Measure the amplitude of both Vin and Vout by oscilloscope.
Determine the voltage gain: Av=Vout/Vin
Measure the phase shift between Vin and Vout.
(ii) Increase Vin gradually at fixed frequency of 100 kHz. Measure the maximum amplitude of Vout without clipping.
4. AC measurement with a load of RL=180 Ω
(i) Set Vin=10 mV in amplitude at a frequency of 100 kHz.
Measure the amplitude of both Vin and Vout by oscilloscope.
Determine the voltage gain: Av=Vout/Vin
(ii) Increase Vin gradually at fixed frequency of 100 kHz. Measure the maximum amplitude of Vout without clipping.
5. Fix Vin amplitude at 10 mV. Increase frequency from 5 kHz to 3 MHz in a series of steps and measure the amplitude of Vout at each frequency.
Note:
• You need more points when Vout changes quickly with frequency around 5 kHz and 3 MHz. The frequency step can be large if Vout does not change much.)
• You may not be able to read Vout accurately at both low and high frequency ends. Try to read it as accurately as you can.
Calculate Av=Vout/Vin for each frequency.
Plot Av against log(frequency). Frequency bandwidth (FB) is defined as the frequency range within which Av/Av(max) ≥ 0.707. Estimate the FB of your amplifier from the Av versus log(frequency) diagram.
6. Design and test additional circuits to increase the effective RL to your amplifier. After a RL=180 Ω is connected, your measurement shows that Av is reduced considerably. Design and verify additional circuits between your amplifier and RL to increase the effective RL to your amplifier, as illustrated below. Evaluate Av for your improved amplifier.
Marking Scheme or Guide to Assessment Criteria
5004ELE Linear electronics (2015/16)
Grade descriptors and feedback sheet Student Name:
Lecturer:
Outcome Below 40% 40 to 49% 50 to 59% 60 to 69% >70% Section Mark /100 Weight Weighted Mark
Understanding amplifier – Analyse the amplifier circuit to explain how the AC signal is amplified with the suitable figures. (I suggest using the simulated result from Proteus) Has a very limited analysis.
Limited analysis. Figures
are not well thought out
Analysis and figures satisfactory with
proper description
Analysis and figures are
good
Excellent demonstration with simulation results showing careful thought. 0.1
Design sections – Design by calculation
a) DC design, setting DC bias.
b) Frequency design
c) AC design and performance evaluation Very limited description, incomplete calculation, missing or seriously incorrect results.
Limited description, minor errors in calculation.
Satisfactory calculation with detailed description.
Correct calculation (no error) with detailed description.
Correct calculation with excellent description and explanation including the discussion on the assumption and approximation made in
the theoretical calculation.
0.4
Verification sections – Verification by simulation
a) Build circuit in Proteus environment
b) Make measurement for DC bias condition
c) Make measurement for AC condition
d) Determine Bandwidth of the amplifier Wrong simulation or not present
Simulation with major errors.
Simulation with minor errors and lack of description and explanation.
Correct simulation result and good description and explanation.
Correct simulation result and excellent description and explanation.
0.3
Design Improvement –
a) Improved amplifier circuit
b) Performance evaluation Very poor improved
design or not present
Poor improved design and no detailed description.
Improved design with minor mistake but no
detailed description
Correct Improved design with detailed description and explanation.
Correct Improved design with excellent description/explanation and the complete performance evaluation. 0.2
Final
Mark
Guide to Performance Criteria
70% and above:
Your work must be of outstanding quality and fully meet the requirements of the coursework specification and learning outcomes stated. You must show independent thinking and apply this to your work showing originality and consideration of key issues. There must be evidence of wider reading on the subject.
Key words which may describe a coursework at this level include: appraises, compares, concludes, contrasts, criticizes, critiques, defends, discriminates, evaluates, explains, interprets, justifies, relates, supports.
60% – 70%:
Your work must be of good quality and meet the requirements of the coursework specification and learning outcomes stated. You must demonstrate some originality in your work and show this by applying new learning to the key issues of the coursework. There must be evidence of wider reading on the subject.
Key words which may describe a coursework at this level include: categorizes, combines, compiles, creates, devises, generates, modifies, reconstructs, identifies, illustrates, outlines, synthesizes.
50% – 60%:
Your work must be comprehensive and meet all of the requirements stated by the coursework specification and learning outcomes. You must show a good understanding of the key concepts and be able to apply them to solve the problem set by the coursework. There must be enough depth to your work to provide evidence of wider reading.
Key words which may describe a coursework at this level include: demonstrates, changes, applies, operates, produces, predicts, shows, solves, uses, translates, comprehends, converts, generalizes.
40% – 50%:
Your work must be of a standard that meets the requirements stated by the coursework specification and learning outcomes. You must show a reasonable level of understanding of the key concepts and principles and you must have applied this knowledge to the coursework problem. There should be some evidence of wider reading.
Key words which may describe a coursework at this level include: comprehends, defines, describes, identifies, knows, labels, lists, matches, outlines, recalls, recognizes, reproduces, selects, states, rewrites.
Below 40%:
Your work is of poor quality and does not meet the requirements stated by the coursework specification and learning outcomes. There is a lack of understanding of key concepts and knowledge and no evidence of wider reading.
Recommended reading
Dr. Neil Storey, ‘Electronics: A Systems Approach’, 4th, 2006.
Extenuating Circumstances
If something serious happens that means that you will not be able to complete this assignment, you need to contact the module leader as soon as possible. There are a number of things that can be done to help, such as extensions, waivers and alternative assessments, but we can only arrange this if you tell us. To ensure that the system is not abused, you will need to provide some evidence of the problem. More guidance is available at http://www.ljmu.ac.uk/corporate/SPR/60399.htm.
Any coursework submitted late without the prior agreement of the module leader will receive 0 marks.
Academic Misconduct
The University defines Academic Misconduct as ‘any case of deliberate, premeditated cheating, collusion, plagiarism or falsification of information, in an attempt to deceive and gain an unfair advantage in assessment’. The School takes Academic Misconduct very seriously and any suspected cases will be investigated through the University’s standard policy (Academic Misconduct Policy). If you are found guilty, you may be expelled from the University with no award.
It is your responsibility to ensure that you understand what constitutes Academic Misconduct and to
For more information you are directed to following the University web pages:
• Information regarding academic misconduct: http://www.ljmu.ac.uk/studysupport/81924.htm • Information on study skills: http://www.ljmu.ac.uk/studysupport/
• Information regarding referencing: http://www.ljmu.ac.uk/studysupport/69049.htm