Download ELTR7011 Exams for Electronic Engineering in Cork Institute of Technology - Summer 2012 and more Exams Electrical Engineering in PDF only on Docsity! Page 1 of 8 CORK INSTITUTE OF TECHNOLOGY INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ Semester 2 Examinations 2012 Module Title: Electronic Engineering Module Code: ELTR7011 School: Electrical & Electronic Engineering Programme Title: Bachelor of Engineering in Electronic Engineering – Year 3 Programme Code: EELXE_7_Y3 EELES_8_Y3 External Examiner(s): Dr. A. Donnellan, Mr. I. Kennedy Internal Examiner(s): Dr. P. O’Connor Instructions: Answer QUESTION 1 (worth 40 marks) and TWO other questions (worth 30 marks each) Duration: 2 HOURS Sitting: Summer 2012 Requirements for this examination: Graph paper, Log Tables Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination paper. If in doubt please contact an Invigilator. Page 2 of 8 1. (a) For the Op-Amp in Fig.1(a), calculate all the currents and voltages around the circuit and state which LED if any lights (RED or GREEN). (DC input voltages are V1 = 1.8V, V2 = 0.5V) (5 marks) (b) Analyse the Op-amp circuit shown in Fig.1(b) and calculate all the voltages and currents around the circuit. (DC input voltages are V1 = 0.8V, V2 = 2V) (5 marks) (c) The Op-Amp shown in Fig.1(c) has a Sinewave input of at a frequency of 1kHz and V2 has a dc value of +1V. Draw a detailed graph of both input and output waveforms using a proper scale and explain your output. (5 marks) (d) An amplifier is displayed in Fig.1(d). It has a Sinewave input of at a frequency of 1kHz. (i) Draw the output signal to a correct scale. (ii) If the frequency of the input is increased to 100kHz what changes if any occur at the output. (Typical Op-Amp values that you are familiar with may be used). (5 marks) (e) Write a technical note on the AC-Performance of Op-Amps. Your explanation should include UGB, )(OLcf , )(CLcf , and a frequency response curve to demonstrate your understanding. (5 marks) (f) An analogue filter’s has a transfer function given by ( ) Sketch its output response and show how you arrived at this response. What type of filter does H(s) represent? (5 marks) (g) Design a boost converter to provide an output of 40V from a 25V source. The load is 50W. The output voltage ripple must be less than 0.8%. Determine the duty cycle, the inductor size and the capacitor value for a chosen frequency. Your design should be for continuous current and assume ideal components. (5 marks) (h) Design a circuit to accomplish the following:- A sensor has an output voltage of ±0.25V. This voltage is fed into a single-supply Op-Amp running off +5V. The output should be centered at 2.4V, with a swing that reaches from 1.66V above ground to 3.16V. Assume that because of the frequencies involved, ac coupling is not an option. (5 marks) Page 5 of 8 Fig.1(a) Fig.1(b) 3 2 6 7 4 1 5 U1 741 R2 6k U1(V+) U1(V-) R3 500 V2 VALUE=0.5V D1 LED-RED VF=2V IMAX=10mA V1 VALUE=1.8V R1 1k D2 LED-GREEN VF=2V IMAX=10mA 3 2 6 7 4 1 5 U1 741 R2 8k U1(V+) U1(V-) R3 2k V2 VALUE=2V V1 VALUE=0.8V R1 2k Page 6 of 8 Fig.1(c) Fig.1(d) 3 2 6 7 4 1 5 U1 741 U1(V+) U1(V-) V2 VALUE=1V R1 5k V(Op-Amp) V1 OFFSET=0 FREQ=1k PHASE=0 THETA=0 AMP=2 R4 3k R3 9k 3 2 6 7 4 1 5 U1 741 U1(V+) U1(V-) R1 5k V(Op-Amp) V1 R4 2k R3 10k Page 7 of 8 Fig.2(a) Fig.2(b) 3 2 6 7 4 1 5 U1 741 U1(V+) U1(V-) V2 V1 FREQ=100 TD=0 AMP=5 OFFSET=0 THETA=0 R1 1k V(Op-Amp) C1 1uF 3 2 6 7 4 1 5 U1 741 U1(V+) U1(V-) V2 V1 FREQ=100 TD=0 AMP=5 OFFSET=0 THETA=0 R1 1k V(Op-Amp-1) C1 1uF 3 2 6 7 4 1 5 U2 741 U2(V+) U2(V-) R2 20k C2 0.25uF U1(Op-Amp-2)
