MODULE DESCRIPTOR
MECH2002 - Applied Electricity & Instrumentation
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MECH2002
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Applied Electricity & Instrumentation
2
0.5/7.5
September
June
Dr. R. Torii
(100%) Module Coordinator
Prerequisites
No previous experience of Instrumentation is required but Applied Electricity to first year level to include
basic electrical circuit components, Ohm’s law, Thevenin and Norton equivalent circuits and Kirchoff’s
current law.
Course Aims
Basic concepts in measurements, accuracy, sources of error. transducers and sensors, their associated
circuitry and dynamic response. The second part of the course is an introduction to operational amplifiers,
characteristics and applications.
Method of Instruction
Lecture presentations, tutorial classes and two laboratory classes.
Assessment
The course has the following assessment components:
 Written Examination (3 hours, 75%)
 One Laboratory Report (25%) written on work undertaken during two lab sessions (E1) and (E2)
To pass this course, students must:
 Obtain an overall pass mark of 40% for all sections combined
The examination rubric is:
Answer FIVE questions (from eight offered). All questions carry equal weight.
Resources
 “Experimental Methods for Engineers” Seventh Edition (2001). J.P. Holman, McGraw-Hill, ISBN
0073660558.
 Nelson, J.C.C. (1995), Operational Amplifier Circuits – Analysis and Design, Butterworth-Heinemann,
MA, USA
 Horrocks, D.H. (1983), Feedback Circuits and Operational Amplifiers, Van Nostrand Reinhold,
Netherlands. (Out of print)
 Ahmad, H. And Spreadbury, D.H. (1984), Analogue and Digital Electronics for Engineers: An
Introductions, 2nd Edn., Cambridge University Press, UK
Additional Information
None
Content
The general measurement system; Instrumentation performance characteristics; accuracy; precision; nonlinearity; sensitivity; resolution; standards; units and dimensions.
Experimental errors; sources of errors; types of errors; error propagation; statistical analysis of experimental
data; least squares analysis; confidence levels.
Measurement of strain; the simple wire strain gauge; the foil strain gauge; the Wheatstone bridge;
temperature compensation; effect of Poisson's ratio on strain measurement; measurement of bending strain;
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measurement of tensile or compressive strain in a bending member; bridge balancing; effect of taking current
from the bridge; Thevenin theorem applied to the Wheatstone bridge; the semiconductor strain gauge.
Measurement of displacement; capacitive displacement transducers; measurement of capacitance;
differential variable separation/area transducers; the phase-sensitive detector; the linear variable differential
transformer; the variable inductance displacement transducer; the inductive bridge circuit; the synchroresolver; the linear inductosyn; resistive potential dividers; the optical incremental shaft encoder; the optical
absolute shaft encoder; optical linear displacement transducers; the magnetostrictive displacement
transducer; wave propagation methods.
Measurement of force; elastic sensing elements; force transducers using the force-balance principle;
piezoelectric force transducers; voltage measurement using an op-amp; charge measurement using a charge
amplifier; Measurement of torque.
Velocity measurement; transducers with a frequency output; the tachogenerator; acceleration measurement;
seismic-mass accelerometer; strain-gauge accelerometer; the potentiometric accelerometer; the servoaccelerometer.
Measurement of temperature; measurement using changes in pressure; thermoelectric temperature sensors;
reference junctions in thermocouples; thermocouple materials and construction; basic metallic resistive
thermometer; thermistors; measuring circuits for resistive sensors; radiation pyrometers.
Dynamic response of measuring systems; first-order dynamic response; step response; sinusoidal response;
second-order dynamic response; transducers with a first order dynamic response; transducers with a second
order dynamic response; frequency response; damping; resonance.
Operational amplifiers; basic non-inverting feedback amplifier; basic inverting feedback amplifier; a summing
amplifier; the input and output resistance; amplifier equivalent circuits at higher frequencies; single-lag
response; frequency compensation; ac amplifiers; Bode gain and phase plots; 3dB bandwidth; feedback
fraction; feedback equation; loop gain; stability in feedback amplifiers; positive feedback; the gain-bandwidth
product; input and output impedances; common-mode rejection ratio, common-mode input impedance; the
virtual-earth approximation applied to a.c.; example of current-derived feedback.
Examples of feedback circuits; RC-active low-pass filter (integrator); the high-pass filter; RC-active band-pass
filter; Wien bridge oscillator; the phase-shifter; the instrumentation amplifier; the voltage-current converter; the
voltage follower; the bootstrapped ac amplifier; non-ideal amplifier properties; input offset voltage; input bias
current; input offset current; remedies for the amplifier non-ideal properties.
General Learning Outcomes
Knowledge and understanding
Measurement techniques and experimental design; performance characteristics of measurement devices;
scientific principles of various types of measurement and the extent of their applicability in engineering
systems.
Skills and attributes
(i) Intellectual
Select an appropriate instrumentation method from an analytical assessment in order to investigate a
specific parameters, such a displacement, rotational speed etc. of a component within an engineering
system.
(ii) Practical
Select and use appropriate test and measurement instrumentation for performance related tasks; select
and conduct appropriate experimental procedures in order to generate appropriate data.
(iii) Transferable
Appraisal of the suitability of the various instrumentation methods in an engineering system.
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