Electronics Measurement and Instruments

1. INTRODUCTION
Mr. Vijay Balu Raskar
B.E. Electrical
Autocad-2D+3D
Mumbai University

2. Electronic
Instruments
and
Measurements

3. Electronic
Derived = Greek word ‘Elektron’ &
‘Electron mechanism’
Electron mechanism= “Study of
behavior of the electrons under
different conditions of externally
applied fields”.

4. Instruments
A device that requires
skill for proper use.

5. Measurements
Measurement is the process
or the result of determining
the ratio of a physical
quantity, such as a length,
time, temperature etc.

6. Refer for EMI
Kalsi –Tata Mc Grow Hill

7. BASICS OF ELECTRICITY
According to
the fundamental law of electromagnetic force

8. Video Time
PRACTICAL - 01

9. In electromechanical
systems, energy is
stored in magnetic and
electric fields.

10. These instrument are appropriately
called as universal instruments.

11. Sr NAME OF PURPOSE
No. EQUIPMENT
1 Ammeter Measures current
2 Voltmeter Measures p.d. between 2 points in circuit
3 Wattmeter Measures the power
4 Multimeter Measures V,I,R,C etc
5 LCR Meter Measures L,C & R
6 Oscilloscope Displays waveform of a signal
7 Ohm-meter Measures R
8 Signal Generator Generates signal for testing purpose
9 Network Analyzer Measures Network parameter
10 Q-meter Measures Q-factor of the RF circuits
(Ratio of reactance to resistance)
11 Etc…………………………………….. ………………

13. AMMETER
An ammeter is a measuring
instrument used to measure
the electric current in a circuit.
UNIT= Amperes (A)
Instruments used to measure smaller
currents, in the milliampere or
microampere range, are designated
as milliammeters or microammeters.

14. WORKING PRINCIPLE OF
AMMETER
An ammeter consists of a
coil with very low resistance.
when electric current flows
through the coil, the coil
induces a magnetic field
which turns the needle.

15. As the current
through the coil
increases,
the plunger is
drawn further
into the coil
and the pointer
deflects to
the right.

16. Wire carrying current to be measured.
Spring providing restoring force

17. Basic Function of Moving Ammeters
With both moving coil and moving iron
ammeters, an electric current is used
to create magnetic energy, which in
turn causes a moving part within the
ammeter to shift in response. The
amount of the shift moves a needle on
the display, which in turn measures
the amount of the current.

18. USE IT ?????
HOW TO USE AMMETER?
HOW TO USE VOLTMETER?
HOW TO USE WATTMETER?
HOW TO USE MULTIMETER?
Calculation of R, L, C etc..
HOW TO USE LCR METER?
HOW TO USE OSCILLOSCOPE?

19. TYPES OF AMMETER

20. Moving Coil Ammeters
In a moving coil ammeter, the magnet
stimulates a coil that has the opposite
polarity, causing it to be repelled from
the magnet.
Moving coil ammeters have a linear
display.

21. Moving Iron Ammeters
In a moving iron ammeter, two
pieces of iron are housed inside
of a coil that becomes
magnetized and repels the two
pieces of iron from one
another. The result is a
nonlinear, arced measurement.

22. Digital Display Ammeters
A digital display has no moving parts,
and instead measures the proportional
drop across a reader located inside of
the ammeter. Digital ammeters are far
more accurate than their moving
counterparts.

24. Indicating:- Indicates magnitude of
quantity being measured.
E.g.- Ordinary
voltmeter, ammeter, wattmeter etc
Recording:- Recording over a specified
period. E.g.- Recording voltages in a
sub-station during the day.

25. Integrating:- Totalize events over a
specified period of time. E.g.-Ampere
Hour Meter (Energy).

26. There are two types of moving coil
instruments.
1. permanent magnet moving coil
type which can only be used for direct
current, voltage measurements.
2.The dynamometer type
which can be used on either direct or
alternating current, voltage
measurements.

27. Permanent Magnet Moving Coil
(PMMC)
The permanent magnet moving coil instruments are
most accurate type for direct current measurements.
The action of these instruments is based on the
motoring principle. When a current carrying coil is
placed in the magnetic field produced by permanent
magnet, the coil experiences a force and moves. As the
coil is moving and the magnet is permanent, the
instrument is called permanent magnet moving coil
instrument. This basic principle is called D’Arsonval
principle. The amount of force experienced by the coil
is proportional to the current passing through the coil.

28. In PMMC meter or (D’Arsonval) meter
or galvanometer all are the same
instrument.

29. Mathematical Representation of
PMMC Mechanism:-
F=N⋅B⋅I⋅L
where ,
N: turns of wire on the coil
I: current in the movable coil
B: flux density in the air gap
L: vertical length of the coil

30. DYNAMOMETER
This instrument is suitable for the
measurement of direct and alternating
current, voltage and power.
The deflecting torque in dynamometer
is relies by the interaction of magnetic
field produced by a pair of fixed air
cored coils and a third air cored coil
capable of angular movement and
suspended within the fixed coil.

31. For small current measurement (5mA
to 100mA), fixed and moving coils are
connected in series.
While larger current measurement
(up to 20A) , the moving coil is shunted
by a small resistance.

32. VOLTMETER
A voltmeter is an instrument
used for measuring electrical
potential difference between
two points in an electric circuit.

33. Working Principle of Voltmeter
The moving coil galvanometer is a
type of voltmeter working on this
principle.
The voltmeter measures voltage by
passing current through a resistance.
It is designed in such a way so as to
offer minimum disturbance to the
circuit. This is made possible by using a
sensitive ammeter in series with a high
resistance.

34. Technically specified, all types of
voltmeters are Ammeters because
they measure current rather than the
voltage. A voltmeter measures voltage
only when current is transmitted in a
circuit through a resistance. Due to
this reason, voltmeters are sometimes
referred to as high resistance
Ammeters too.

35. Uses of Voltmeters
Voltage Sensing
Voltage Measurement
Electrical Testing
Educational Laboratory
Electronics Industry

36. Types of Voltmeters
1.Digital Voltmeters
2.Analog Voltmeters
3.Electrostatic Voltmeters (measure voltages
without any charge transfer)
4.Oscilloscope Voltmeter(react fast enough
to follow rapid voltage changes)
5. Microvoltmeters
6. Electronic voltage meter or
vacuum tube voltmeter (VTVM)

37. Oscilloscope
Allows the amplitude of electrical
signals, whether they are
voltage, current; power, etc., to be
displayed primarily as a function of
time.
Depends on the movement of an
electron beam.
Beam to impinge on a phosphor
surface

38. Transducers
Non-electrical quantity is
converted into an electrical signal by a
device called electrical transducer.
Non-electrical = electrical, mechanical,
chemical, optical (radiant), or thermal.

39. Types of Transducers
1. Primary & Secondary
2.Active & Passive
3.Analog & Digital

40. Primary Transducer
Converts energy from one form to
electrical form (photovoltaic cell)
Secondary transducer
Coverts any form to non electrical or
signal form.(displacement transducer)

41. Active (self generating) transducers:-
without any source of electrical
excitation.
(thermocouples, tacho generator)
passive transducers:
in connection
with electrical power source.
(a potentiometer, thermistor)

42. Analog transducer converts input
signal into output signal, which is a
continuous function of
time.
Digital transducer converts input
signal into output signal in a discrete
forms.

43. Displacement Transducer
convert the applied force into a
displacement.
Measured by following
Electrical Principle:
1) Capacitive 2) Inductive
3) Differential transformer
4) Photoelectrical 5) Potentiometer
6) Ionization 7) Oscillation
8) Piezoelectric 9) Velocity

44. LVDT
(Linear Variable Differential Transformer)
It is produces an electrical signal
that is linearly proportional to
mechanical displacement.

46. emf opposes each other.
Left when more flux links and so on

47. I am adding more slides.
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48. THANK YOU

49. CONTACT
vijayraskar2003@yahoo.co.in
vijay.raskar1986@gmail.com
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