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S142 01/10/
THE MANCHESTER METROPOLITAN UNIVERSITY
FACULTY OF SCIENCE AND ENGINEERING
DEPARTMENT OF ENGINEERING AND TECHNOLOGY
SESSION 2003/
Examination for the BEng (HONS) ELECTRICAL AND ELECTRONIC ENGINEERING HND ELECTRONIC ENGINEERING YEAR/STAGE ONE
UNIT 64EE1102 : ANALOGUE ELECTRONICS
Tuesday 18 May 2004
9.30 am to 11.30 am
Instructions to Candidates
Attempt FOUR questions.
Marks for sections of questions are shown in parentheses.
You are permitted to use any calculator which conforms to the Faculty Standard.
01/10/2004 continued
- (a) The circuit of a common emitter amplifier is shown in Figure Q1. If the quiescent voltages at the emitter and collector are 2V and 15V respectively, calculate the following but do not use NPV (nearest preferred values):
(i) the value of R 3 , assuming I (^) E=I (^) C ; [2]
(ii) suitable values for R 1 and R 2 assuming h (^) FE(MIN)=200 and VBE =0.7V for the transistor; [4]
(iii) a new value of R 3 , to obtain maximum output swing. [4]
(b) R2 is now removed from the circuit and R 1 is replaced by a 1M Ω resistor. Using the original value for R 3 found in (a) above, calculate the quiescent voltages at the collector and emitter assuming hFE=300 and VBE=0.7V. Briefly explain why this circuit is less desirable than the original. [15]
- (a) Name THREE properties of an ideal operational amplifier. [6]
(b) Explain what is meant by the term 'virtual earth' when applied to an operational amplifier circuit. [3]
(c) Draw the circuit diagram of a differential amplifier and derive an expression for the output voltage in terms of the input voltages and resistances in the circuit. [16]
S142 01/10/
- Figure Q5 depicts the trajectories of 6 holes within a vertical, silicon, PNP Bipolar Junction Transistor.
Figure Q5 (© Milward 1955)
(a) State what is meant by carrier ‘ recombination’. [2]
(b) State how base width changes BJT operation. [3]
(c) State why there is a depression seen in the ‘surface’ around the base terminal. [2] (d) State what is occurring when the base region is energised to the potential depicted by the letters A & B. [2]
(e) Sketch an electronic circuit schematic that could provide these bias conditions. [2] (f) Labelling the holes shown, (from left to right),numbers 1 -> 6; state, and creating a table to help in your explanation, state the conditions that gave rise holes 1, 2, 4, 5 individual path. [12]
(g) If the transistor were manufactured from germanium instead of silicon, explain how appearance of Figure Q5 might change. [2]
END
