Analogue Electronics Digital Electronics - 2000 2001 Exam - Electrical Engineering, Exams of Electrical Engineering

Download Analogue Electronics Digital Electronics - 2000 2001 Exam - Electrical Engineering and more Exams Electrical Engineering in PDF only on Docsity! S318 06/09 /02 TH E MANCH ESTER M ETR O PO LITAN UNIVER SITY FACULTY O F SCIENCE AND ENGINEER ING D EPA R TMENT O F ENGINEER ING AND TECH NO LO GY SESSIO N 2000/2001 Exam ination for th e BEng (H O NS) ELECTR ICA L AND ELECTR O NIC ENGINEER ING H ND ELECTR O NIC ENGINEER ING YEA R O NE UNIT 64EE1006/64EE1007/64EE1072/64EE1073 ANALO GUE ELECTR O NICS/D IGITAL ELECTR O NICS Th ursday 24 May 2001 2.00 pm to 4.00 pm Instructions to Candidates A nsw er FO UR questions, TW O from EACH section. continued 1 SECTIO N A 1. (a) Th e circuit of a com m on em itter am plifier is sh ow n in Figure Q 1. If th e quiescent voltages at th e em itter and collector are 2V and 10V respectively, calculate th e follow ing but do not use NPV (nearest preferred values): (i) th e value of R 3 assum ing IE=IC; [2] (ii) suitable values for R 1 and R 2 assum ing h FE(MIN)=200 and VBE=0.7V for th e transistor; [4] (iii) a new value of R 3 to obtain m axim um output sw ing. [4] (b) R 2 is now rem oved from th e circuit and R 1 is replaced by a 2MΩ resistor. Using th e original value for R 3 found in (a) above, calculate th e quiescent voltages at th e collector and em itter assum ing h FE=300 and VBE=0.7V. Briefly explain w h y th is circuit is less desirable th an th e original. [15] Figure Q 1 2. (a) Nam e th ree properties of an ideal operational am plifier. [6] (b) Explain w h at is m eant by th e term ‘virtual earth ’ w h en applied to an operational am plifier circuit. [3] (c) D raw th e circuit diagram of a differential am plifier and derive an expression for th e output voltage in term s of th e input voltages and resistances in th e circuit. [16] R 3 R 4 1k Ω R 1 R 2 Vcc = 20V