1
Cork Institute of Technology
Bachelor of Engineering in Electrical Engineering - Stage 1
(NFQ – Level 7)
Autumn 2007
Industrial Electronics
(Time: 3 Hours)
INSTRUCTIONS:
Answer Five Questions.
All formula and calculations must be shown.
Examiners: Mr. R. Daly
Prof. E. Mc.Quade
Mr. M. Hennessy
Q1 (a) What is the purpose of rectifiers in electronic equipment? 2 marks
~
~
D1
D4
D2
D3
230 V
50 Hz. 18 V C
+
A
B
C
D
Fig.1
(b) Using the reference points in Fig. 1, explain (ignoring the capacitor) the operation of the
full-wave bridge rectifier circuit and indicate the polarity at the output terminals
C and D. 8 marks
(c) Show the waveforms with important values for:
(i) The voltage at AB; 3 marks
(ii) The voltage at CD without the capacitor connected; 3 marks
(iii) The smoothed output at CD. 4 marks
Q2 (a) Construct a 5-column binary table with appropriate headings to represent the decimal
numbers from 0 to 15. Write the decimal digits in the left hand column. 6 Marks
(b) Draw the circuit logic symbols and truth tables for, a 2-input AND gate, and a 2-input
XOR gate. 6 Marks
(c) Show how the gates in (b) can be connected to construct a half-adder. Include in your
answer the truth table for the half-adder. 8 Marks
