Measurements and Instrumentation

At the end of the course, the student should be able to: 1. analyse the performance characteristics of each instrument; 2. illustrate basic metres such as voltmetres and ammetres; 3. explain about different types of signal analyseanalysers; 4. explain the basic features of oscilloscope and different types of oscilloscopes; and 5. apply the complete knowledge of various electronics instruments/transducers to measure the physical quantities in the field of science, engineering and technology.

Introduction: Significance of Measurement and block diagram of Measurement System, Static characteristics- Accuracy, Precision, Sensitivity, Linearity, Repeatability, Reproducibility, Resolution, Threshold, Drift, Stability, Dead zone, hysteresis, Dynamic Characteristics- speed of response, measuring lag, fidelity, dynamic error, Types of Errors – Gross error, systematic errors, Random errors. Measuring Instruments: PMMC, DC voltmetre and current metres and its Extension ranges, True RMS Responding Voltmeter, Average responding rectifier type voltmetre, electronic voltmetre, block diagram approach for measurement of voltage, current and Resistance using Digital Multi Metre (DMM), Basic Potentiometer Circuit, Q-meter – Series Method. Bridges and AnalyseAnalysers: DC Bridge- Wheatstone bridge, Kelvin's Double Bridge, AC Bridge- Maxwell’s Bridge, Schering bridge and Wien’s Bridge. Signal Analysers: Frequency Selective and Heterodyne Wave Analysers, Harmonic distortion Analysers, Total Harmonic distortion, Spectrum AnalyseAnalysers. Oscilloscopes: Cathode Ray Tube (CRT), Electrostatic Deflection, Post-deflection and Acceleration of Electron Beam, Screens for CRT’s, Block diagram of CRO, Time-based Generator, Delay line, Attenuators, probes, Dual beam oscilloscope, Dual trace oscilloscope, Digital Storage Oscilloscope, Applications of CRO: Measurement of Phase and Frequency using Lissajous Patterns. Transducers: Transducer and its classification, ideal features of Transducer – Resistive Transducer: Potentiometric type, Strain Gauge type (Gauge factor derivation, SG materials, Bonded and unbounded strain gauges), Capacitive Transducers - Variable gap type, variable area type and variable Dielectric type, Inductive Transducers - LVDT, Thermocouple, Thermistor, Piezo Electric Transducers, Piezoelectric effect, Piezoelectric materials, RTD, photo voltaic cell, LDR.