Electrical Measurements Pdf Notes – EM Pdf | Free Lecture Notes download


Here you can download the free lecture Notes of Electrical Measurements Pdf Notes – EM Pdf Notes materials with multiple file links. The Electrical Measurements Notes Pdf – EM Notes Pdf book starts with the topics covering control and damping torques, design considerations Type of P.F. Meters, Double element and three element dynamometer wattmeter,  errors and compensations, Measurement of unknown resistance, Method of measuring low, Measurement of inductance, Ballistic galvanometer, Etc.

Electrical Measurements Notes - EM Notes - EM Pdf Notes
Electrical Measurements Notes Pdf – EM Notes Pdf

Electrical Measurements Pdf Notes – EM Pdf Notes

The Electrical Measurements Notes Objective :

Electrical measurements course introduces the basic principles of all measuring instruments. It also deals with the measurement of RLC parameters voltage, current Power factor, power, energy and magnetic measurements.

Electrical Measuremente Notes

Complete notes:

Download EM Notes here



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.


Instrument transformers

CT and PT – Ratio and phase angle errors – design considerations Type of P.F. Meters – dynamometer and moving iron type – 1-ph and 3-ph meters – Frequency meters – resonance type and Weston type – synchroscopes.


Measurement of Power

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.


Measurement of Energy

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 – trivector meter, maximum demand meters.

Electrical Measurements Notes Pdf (EM Notes)



Principle and operation of D.C. Crompton’s potentiometer – standardization – Measurement of unknown resistance, current, voltage.

A.C. Potentiometers: polar and coordinate types standardization – applications.


Resistance Measurements

Method of measuring low, medium and high resistance – sensitivity of Wheatstone’s bridge – Carey Foster’s bridge, Kelvin’s double bridge for measuring low resistance, measurement of high resistance – loss of charge method.


A.C. Bridges

Measurement of inductance, Quality Factor – Maxwell’s bridge, Hay’s bridge, Anderson’s bridge, Owen’s bridge. Measurement of capacitance and loss angle – Desauty bridge. Wien’s bridge – Schering Bridge.


Magnetic Measurements:

Ballistic galvanometer – equation of motion – flux meter – constructional details, comparison with ballistic galvanometer.


  1. Electrical Measurements and measuring Instruments – by E.W. Golding and F.C. Widdis, fifth Edition, Wheeler Publishing.
  2. Electrical & Electronic Measurement & Instruments by A.K.Sawhney Dhanpat Rai & Co. Publications.


  1. Electrical Measurements – by Buckingham and Price, Prentice – Hall
  2. The Electrical Measurements by Harris.
  3. Electrical Measurements: Fundamentals, Concepts, Applications – by Reissland, M.U, New Age International (P) Limited, Publishers.

Note :- These notes are according to the R09 Syllabus book of JNTUH. In R13 ,8-units of R09 syllabus are combined into 5-units in r13 syllabus.Click here to check all the JNTU Syllabus books 

Frequently Asked Questions

Q1: What are the classification of measuring instruments?

A1: Classification of measuring instruments are,

  1. Indicating instruments which make use of dial and pointer. These show or indicate unknown quantity’s magnitude. Voltmeter or ammeters are some of the examples
  2. Recording instruments are continuous recording of the provided electrical quality that is being measured over a specific period of time.
  3. Integrating instruments are used to measure the quantity of electricity delivered over a period of time.

Q2: What are the essential requirements of an instrument?

A2: Essential requirements of an instrument include,

  • Deflecting system which produces deflecting torque
  • Controlling system which produces controlling torque
  • Damping system which produces damping torque

Q3: What are the different effects produced by a current or voltage for a deflecting system to produce deflecting torque?

A3: Different effects produced by a current or voltage for a deflecting system to produce deflecting torque are,

  • Thermal effect
  • Induction effect
  • Hall effect
  • Magnetic effect
  • Electrostatic effect

Q4: What are the differences between Gravity control and Spring control?

A4: Difference between gravity control and spring control are

Gravity control Spring control
To produce controlling torque adjustable small weight is used To exert controlling torque two hair springs are used
The torque can vary Torque is fixed
Performance is not dependent on temperature Performance is dependent on temperature
Scale is not uniform Scale in uniform
Reading in gravity control cannot be taken accurately Reading in spring control can be taken accurately
System should be used  in Vertical position No compulsion  that system should be used in vertical position
Delicate, cheap and simple Rigid, costly and simple

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