Download Avalanche Breakdown - Analogue Electronics - Exam and more Exams Digital & Analog Electronics in PDF only on Docsity! 1 ELTR 6003 CORK INSTITUTE OF TECHNOLOGY INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ Summer Examinations 2010 Module Title: Analogue Electronics 2 Module Code: ELTR6003 School: Electrical & Electronic Engineering Programme Titles: Bachelor of Engineering in Electronic Engineering Bachelor of Engineering (Honours) in Electronic Systems Engineering Programme Codes: EELXE_7_Y1 EELES_8_Y1 External Examiner(s): Dr. A. Donnellan Dr. P. O’Sullivan Internal Examiner: Mr. M. O’Gorman Instructions: Answer Question 1 and TWO other questions. Question 1 (worth 40 marks) is compulsory. Questions 2, 3, and 4 are each worth 30 marks. Duration: 2 Hours Sitting: Summer 2010 Requirements for this examination: N/A Note to Candidates: Please check the Programme Title and the Module Title to ensure that you are attempting the correct examination paper. If in doubt please contact an Invigilator. 2 ELTR 6003 COMPULSORY QUESTION Q. 1 (a) Sketch typical output characteristics for a common emitter transistor and illustrate the region where the transistor is said to be saturated. What bias condition exists at the collector-base junction (VCB) when a transistor operates in the saturated region? [10 marks] (b) Briefly distinguish between avalanche breakdown and zener breakdown in a reverse-biased pn-junction. [10 marks] (c) With reference to transistor amplifiers, explain what is meant by the term stabilisation of the operating point. [10 marks] (d) Show how the maximum power dissipation curve for a transistor may be drawn on the transistor’s output characteristics. Illustrate the direction of curve displacement if the ambient operating temperature of the device is to be increased. [10 marks] CHOOSE TWO QUESTIONS FROM Q.2, Q.3, OR Q.4. Q. 2 (a) Draw the circuit diagram of a simple zener diode voltage regulator and briefly explain how the circuit minimises the effects of supply voltage variations on the load voltage. [8 Marks] (b) A zener diode has a reverse breakdown voltage of 9.1V and after this may be considered to be a linear resistance of 18Ω. A simple voltage stabilising circuit using the diode above is to maintain 10V across a constant 500Ω load from a nominal 13.5V supply. Draw the circuit diagram and calculate the value of series resistor required. [12 Marks] (c) If the supply voltage increases by 20%, calculate; (i) the change in load voltage, (ii) the change in diode power dissipation. [10 Marks]
