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Autumn Examinations 2008/ 2009
Exam Code(s) 1BN, 1BP, 1BEE
Exam(s) 1
st
Electronic Engineering
st
Electronic & Computer Engineering
st
Sports and Exercise Engineering
Module Code(s) EE
Module(s) Analogue Electronics
Paper No. 1
Repeat Paper Yes
External Examiner(s) Professor George Irwin
Internal Examiner(s) Professor Gearóid ÓLaighin
Mr. Gavin Corley
Dr. Edward Jones
Instructions: Answer all of question 1, and any 2 other questions
Question 1 is compulsory and carries 40 marks
Choose 2 questions from 2,3 & 4; each question
carries 3 0 marks
Duration 2 hours
No. of Pages 7 (including cover page)
Department(s) Electrical & Electronic Engineering
Course Co-ordinator(s) Gavin Corley
Requirements :
MCQ
Handout
Statistical Tables
Graph Paper
Log Graph Paper
Other Material Standard Mathematical Tables
Question 1 is compulsory
1. (a) For the circuit shown in Figure 1.1 calculate: (i) The total resistance of the circuit, RT [4 marks]
(ii) The total current IT, flowing in the circuit [1 marks]
Figure 1.
1. (b) For the circuit shown in Figure 1.2 calculate: (i) The value of the load resistor (RLoad) which will ensure maximum power transfer to the load. [3marks] (ii) The maximum power dissipated in RLoad [2 marks]
Figure 1.
1. (c) From the sawtooth waveform shown in Figure 1.3 calculate: (i) The period (T) of the waveform. [1 marks] (ii) The frequency (f) of the waveform. [1 marks] (iii) The DC offset of the waveform. [1 marks] (iv) The amplitude of the waveform. [1 marks] (v) The peak to peak value (Vp-p) of the waveform [1 marks]
Figure 1.
1. (g) Calculate the RMS current flowing in the circuit shown in figure 1.6 and specify the phase angle of the current: [5 marks]
Figure 1.
1. (h) Draw a complete circuit diagram of a half wave rectifier and briefly explain its operation.
[5 marks]
2. For the circuit of Figure 2:
(a) Calculate the current flowing in the 60Ω resistor due to the 50V voltage source. [7 marks]
(b) Calculate the current flowing in the 60Ω resistor due to the 20V voltage source. [7 marks]
(c) Calculate the current flowing in the 60Ω resistor due to the 3A current source. [7 marks]
(d) Using the principle of superposition, calculate the total current and power dissipated in the 60Ω resistor. [9 marks]
Figure 2
4. (a) Figure 4 shows a series connected RLC circuit.
(i) Determine the total impedance (Z) of the circuit. [5 marks]
(ii) Find the value of the capacitor in Farads and the inductor in Henries. [5 marks]
(iii) Calculate the magnitude of the supply current I , and voltages VR, VL,VC. [5 marks]
(iv) What is the average power delivered to the circuit? [5 marks]
Figure 4
(b) A smoothing capacitor is to be added to a half wave rectifier circuit with input: v( t ) = 10sin(120 πt ) and load resistance RL = 3kΩ.
(i) Calculate the value of the capacitance necessary in order to keep the ripple of the output voltage below 10%. [6 marks]
(ii) Plot two cycles of the smoothed output voltage waveform. Specify an approximation to the average output voltage when the smoothing capacitor is attached. [4 marks]
