Cork Institute of Technology
Bachelor of Engineering in Electronic Engineering – Stage 2
(EELXE_7_Y2)
Summer 2008
Analogue Electronics
(Time: 3 Hours)
Answer Question one and any four other
questions.
Note: All questions do not carry equal marks
Examiner: Mr. T Connolly
Mr. D. Denieffe
Dr. P. O Sullivan
Q1.Compulsory
(a) Draw the circuit diagrams of each of the following
(i) OP-AMP differentiator
(ii) Three input summing amplifier
(iii) Source follower
(iv) Unity gain non inverting amplifier
(v) OP- AMP difference amplifier [10 marks]
(b) Draw the frequency response of an A.M. I.F. amplifier. Give a typical value for the I.F.
frequency and state the 3dB bandwidth of the AMP. [6
marks]
(c) Give the formula for the overall noise figure of two amplifiers connected in cascade. An
amplifier with a gain G = 23dB and noise figure F = 6dB is connected in series with an
attenuator of 4dB to provide an overall gain of 19dB. Calculate the two possible overall noise
figures. Comment on the results. [6
marks]
(d) A frequency modulator has a sensitivity of 5kHz/v. Calculate the bandwidth required when a
modulation signal of 5v peak at 10kHZ is applied to the modulator. [6 marks]
Q2. (a) Draw the small signal equivalent circuit of a bi-polar transistor. Explain each
component in the diagram. [4 marks]
(b) Draw the circuit diagram of an emitter-follower. [3 marks]
(c) Draw the small signal equivalent circuit of the amplifier in part (b) [3 marks]
(d) Using the circuit in part (c), derive the equations for input resistance and voltage gain of an
emitter follower. [8 marks]
