UNIT - I: Introduction to Measuring Instruments Classification - deflecting, control and damping torques -Ammeters and Voltmeters -PMMC, moving iron type instruments - expression for the deflecting torque and control torque - Errors and compensations, extension of range using shunts and series resistance. Electrostatic Voltmeters electrometer type and attracted disc type - extension of range of E.S. Voltmeters. (Chapter - 1) UNIT - II: Potentiometers & Instrument Transformers Principle and operation of D.C. Crompton's potentiometer-standardization-Measurement of unknown resistance, current, voltage. A.C. Potentiometers: polar and coordinate type's standardization - applications. CT and PT - Ratio and phase angle errors. (Chapter - 2) UNIT - III: Measurement of Power & Energy Single phase dynamometer wattmeter, LPF and UPF, Double element and three element dynamometer wattmeter, expression for deflecting and control torques - Extension of range of wattmeter using instrument transformers - Measurement of active and reactive powers in balanced and unbalanced systems. Single phase induction type energy meter - driving and braking torques - errors and compensations-testing by phantom loading using R.S.S. meter. Three phase energy meter-tri-vector meter, maximum demand meters. (Chapter - 3) UNIT - IV: DC & AC Bridges Method of measuring low,medium and high resistance - sensitivity of Wheat-stone's bridge - Carey Foster's bridge, Kelvin's double bridge for measuring low resistance, measurement of high resistance -loss of charge method. Measurement of inductance- Maxwell's bridge, Hay's bridge, Anderson's bridge - Owen's bridge. Measurement of capacitance and loss angle -Desaunty's Bridge - Wien's bridge-Schering Bridge. (Chapter - 4) UNIT - V: Transducers Definition of transducers, Classification of transducers, Advantages of Electrical transducers, Characteristics and choice of transducers; Principle operation of LVDT and capacitor transducers.
