Cork Institute of Technology
Higher Certificate in Engineering in Biomedical Engineering – Award
(NFQ Level 6)
Summer 2007
Biomedical Devices
(Time: 3 Hours)
Answer Four Questions
All questions carry equal marks
Examiners: Prof. P. McHugh
Mr. M. Murphy
Mr. G. Flynn
Dr. K. Bryan
Q1. (a) Describe, with respect to electrical medical devices, what an “Effective ground” is.
Give an example to explain your answer.
What would happen if the “Effective ground” becomes defective? (5 marks)
(b) What measures are used in the design of electrical medical devices to reduce the risk of
electrical shock to the patient?
If AC current is allowed to flow through the body what is the minimum value that will
cause death?
Use diagrams to explain “Enclosure leakage current”. What measures are taken to reduce
this risk? (8 marks)
(c) Use diagrams to explain the difference between “Patient leakage current” and “Earth
leakage current”.
Why is an “earth wire” used in electrical equipment? Explain your answer. What is the
significance in a fuse rating? (12 marks)
