Resit Assignment

This assignment fulfils the resit requirements to pass this credit.

It must be submitted by 4 p.m. on 17th August 2016.

The report must be submitted ON PAPER to the EEE Resource Centre,

4th floor, Royal College Building, Room Number R4.01.

It can be handed in personally, or posted. Optional, electronic

submission by email is not permitted.

The postal address is:

EEE Resource Centre

Ref. EE108 (19260)

University of Strathclyde

Royal College Building

204 George Street

Glasgow G1 1XW, UK

A receipt will be provided.

Submissions after this date and time, or failure to submit, will result in a

mark of zero being returned to Registry.

IMPORTANT:

You must complete the standard coursework Cover Sheet and attach

it to the front of your solutions. This is available from the EEE

Resource Centre or from

https://moss.strath.ac.uk/eee/sip/site/course-information/eee-

45/Documents/cover11.pdf

Write your name and student registration number on your answer

sheets.

Students are reminded of the requirement that the submission is

subject to University and Departmental regulations with regards to

originality and academic practise.

2 of 9

Q1) The circuit shown in Figure Q1 is used as part of an engine

management system for a modern car. It determines when the engine

temperature exceeds a threshold value. The input signal from the

temperature sensor is entered at point A.

(10 Marks Total for Q1)

+ _

A

Input

signal

B

C

1k

R1 = 3k

Figure Q1

Q1A) If the sensor signal shown in figure Q1A is entered at point A,

sketch the signal observed at points B and C. Indicate the actual

magnitudes of the signals. Demonstrate all the calculations used and

explain how you came up with your answers.

5 Marks

-0.012 V

0 V

Figure Q1A

Q1B) The designer decides to alter the design of the circuit. Resistor

R1 is now changed to be 1kΩ. If the sensor signal shown in figure Q1A

is again entered at point A, sketch the signal observed at points B and

C. Indicate the actual magnitudes of the signals. Demonstrate all the

calculations used and explain how you came up with your answers.

5 Marks

Q2) Analogue to Digital Conversion:

(10 Marks Total for Q2)

Q2A) Explain the difference between an analogue signal and a digital signal.

2 Marks

3 of 9

Q2B) Explain what binary coded decimal (BCD) is.

2 Marks

Q2C) The circuit in Q1 is a form of analogue to digital conversion. Within the

engine management system, we wish to count the number of times the engine

temperature threshold is breached. Therefore, we wish to attach a Binary

Coded Decimal (BCD) counter to point C. Draw a diagram of the BCD counter

circuit we need to construct, and explain in detail how it operates (from the

basis of the JK Flip-Flops). We need to count up to a maximum of 99

temperature warnings.

6 Marks

Q3) Internal Resistance:

(18 Marks Total for Q3)

A B

25V

10 5

20

20

5

5

25

20

30

30

10

Figure Q3

Q3A) For figure Q3, if we wish to measure IAB and VAB, draw a diagram that

shows how we would connect an ammeter and a voltmeter.

2 Marks

Q3B) Explain the impact of the internal resistance in the ammeter and

voltmeter. Ideally, what values would we like them to be and why?

2 Marks

Q3C) A student was asked to design a new voltage meter. Once completed, it

had an internal resistance of 500. She then used it to measure VAB in the

circuit shown in Figure Q3. What is the measured value of VAB and what is the

correct value of VAB ?

10 Marks

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Q3D) Draw the circuit showing clearly how she could adapt her meter

connection, using a device or circuit employing an op-amp as taught in the

lectures, to measure the correct value of VAB.

2 Marks

Q3E) In the circuit shown in Figure Q3 (with the voltage meter connected),

what is the power dissipated in the meter?

2 Marks

Q4) Figure Q4 shows a Wheatstone bridge circuit arrangement, with a

Thermistor (RT) as part of it. We can assume that RT = 3.4kΩ at 20oC.

The manufacturer’s sheet gives the temperature coefficient of the

thermistor as 5% / oC at 20oC.

(4 Marks Total for Q4)

15 V

1.7k 1.7 k

RT

A B

3.4k

3k

Figure Q4

Q4A) What is the output VAB at 20oC?

1 Mark

Q4B) What is the output VAB at 17oC?

2 Marks

Q4C) Why do we use a Wheatstone bridge for measurement circuits?

1 Mark

5 of 9

Q5) For the circuit shown in Figure Q5:

(4 Marks Total for Q5)

8

5V

A B

4A 3

Figure Q5

Q5A) What is the Thevenin equivalent circuit?

2 Marks

Q5B) What is the Norton equivalent circuit?

2 Marks

Q6) With reference to the circuit shown in Figure Q6, determine the

Thevenin equivalent circuit between A and B, and calculate what the

voltage across a 3 resistor connected between A and B would be.

(4 Marks Total for Q6)

A B

20A

0.2 0.15

5A

10A 0.05

Figure Q6

6 of 9

Q7) For the circuit on Figure Q7, DESIGN and DRAW the op-amp circuit

which will give an output of –20V

(10 Marks Total for Q7)

2

4 4 2

2

20V

18

Op-amp

Circuit

–20V

Figure Q7

Q8) In the circuit shown in Figure Q8, determine, using Kirchhoff’s laws,

the magnitudes and signs of the currents I1, I2 and I3. Find also the

magnitude and sign of the potential difference VAD.

(8 Marks Total for Q8)

R1=10

R4

=40

+ R2=20

+

V1=1V V3=3V

A B C

D

I1=? I3=?

I2=?

V2=2V

R3=30 +

Figure Q8

7 of 9

Q9) Figure Q9 shows an ultrasonic non-destructive testing probe for a

metal plate:

(15 Marks Total for Q9)

0 2 4 6 8 10 plate

initial

pulse

Echo

1

Echo

2

Oscilloscope Crack/defect

Coupling gel

Figure Q9

Q9A) Describe what is meant by non-destructive testing? Why are ultrasonic

methods good for this?

2 Marks

Q9B) Explain what causes echo 1 and echo 2 on the oscilloscope?

2 Marks

Q9C) Explain the role of the coupling gel?

2 Marks

Q9D) Explain what is meant by pulse repetition frequency (PRF) in ultrasonic

non-destructive testing. Why is this an important value to calculate?

2 Marks

Q9E) If the metal plate in figure Q9 is made of steel, is 10 cm deep, and has

no defects then what is an appropriate PRF that should be used?

5 Mark

Q9F) If we use the pulse excitation circuit shown in Figure Q9F, what value

should R1 be set to?

2 Marks

8 of 9

+5V

0V

R1

C1 = 1μF

150

33

E B1

B2

2

3

1

Figure Q9F

Q10) For the circuit in Figure Q10:

(5 Marks Total for Q10)

2

4

VS

8

16

32

64

32

64

0.1A

Figure Q10

Q10A) What is VS? Show the working.

5 MARKS

Q11) AC Circuits: Calculate the magnitudes and signs of the current i12

which will flow in a 10F capacitor under the following conditions:

(6 Marks Total for Q11)

Q11 A) v12=+50V and decreasing in magnitude at a rate of 104 V/s;

2 MARKS

Q11 B) v12 is constant at a value of 38V;

2 MARKS

Q11 C) v12=-500V and its magnitude is increasing at a rate of 600 V/s;

2 MARKS

Q12) AC Circuits: An ac power source has a peak output voltage of

340V:

(6 Marks Total for Q12)

Q12A) Calculate the power dissipated in a 100 resistor connected to the

source.

2 MARKS

9 of 9

Q12B) What is the rms current flowing through the resistor?

2 MARKS

Q12C) What is the peak value of the current?

2 MARKS

END OF PAPER