Absolute and secondary instruments, Types of secondary instruments, Essentials of indicating instruments, Constructional details of indicating instruments. Principle of induction type instruments- shaded pole method and two pole methods, compensation for frequency and temperature errors. Induction type voltmeter, Ammeter, advantage and disadvantages, induction type single phase watt hour meter , their errors and remedies, Numerical, wattmeter, power fractometer, etc. Characteristics of Instruments and Measuring Systems: Elements of generalized measuring system, static calibration, accuracy, sensitivity, reproducibility, static errors, dead zone, drift in measuring instruments. Analog and digital representation of signals, Factors influencing the choice of transducers. Mechanical Input Transducers: Level, Pressure, Flow, Velocity and Humidity- Resistive, Capacitive and Inductive, Dielectric system for humidity measurements. Temperature Transducers : Resistive, inductive, capacitive and thermoelectric transducer. Magnetic Transducers : Systems based on induction and magnetic effects on moving charges, Transducers based on permeability variation.