This document provides an overview of electrical and electronic measurements. It discusses measurement systems and instruments, including various types of analog and digital meters, bridges for measuring resistance, inductance and capacitance, signal generators and oscilloscopes. Measurement methods can be direct or indirect, with indirect using a transducer and processing the signal. Key aspects covered include instrument components, types of instruments, and their functions such as indicating, recording and integrating measurements.

1. ELECTRICAL AND ELECTRONIC
MEASUREMENTS

2. SYLLABUS
OVERVIEW

3. UNIT-I MEASUREMENT
SYSTEM AND MEASURING
INSTRUMENTS
Generalized Measurement system,
Classification of instruments, Error in
measurement, Classification of errors.
Principle, Construction, Operation of
Moving Coil and Moving Iron Instruments -
Ammeters and Voltmeters - Single phase
Watt meters and Energy Meters - D.C &
A.C Potentiometers - Instrument
Transformers- Instruments for
Measurement of Frequency and Phase-
Calibration of watt meter.

4. UNIT-II MEASUREMENT OF
R,L,C USING BRIDGES
D.C Bridges: Wheatstone - Kelvin double
bridge- Megger – A.C Bridges: Anderson
Bridge –Maxwell Bridge- Hay’s Bridge
and Schering bridge - Measurement of
Unknown Capacitance using Schering
Bridge.

5. UNIT-III ELECTRONIC
INSTRUMENTS
Analog Meters: D.C Ammeter and Voltmeters
- Multimeter - Q meter - True RMS Meter -
Vector Impedance Meter - RF Voltage and
Power Measurements - Instrumentation
Amplifier.
Digital Meters: Digital Tachometer – DMM-
ADC: Successive Approximation, Dual
Slope –DAC: Weighted Resistor, R-2R
Ladder type- Digital Frequency Counters -
LCR meter- Calibration of DC Ammeter
and DC Voltmeter.

6. UNIT-IV DIGITAL STORAGE
OSCILLOSCOPE AND SIGNAL
GENERATORS
Analog Storage Oscilloscope - Sampling
Oscilloscopes - Digital Storage
Oscilloscopes - Sine Wave Generator -
Sweep Frequency Generator, Pulse and
Square Wave Generator - Wave
Analyzer: Harmonic Distortion Analyzer -
Spectrum Analyzer- Measurement of
frequency and voltage at different ac
inputs using DSO.

7. UNIT-V SMART
INSTRUMENTS AND
RECORDERS
Serial, Parallel ports, USB–IEEE 488-
Applications of Digital Instruments-
Elements of Data Acquisition - Smart
Sensor. Acquiring and Generating
Signals using DAQ Card.
Recording Devices: X-Y Plotters, Magnetic
Tape Recording - Data Loggers- Display
Devices: LED, LCD

8. MEASUREMENT
The measurement of a given quantity is
essentially an act or the result of
comparison between the quantity
(whose magnitude is unknown) and a
predefined standard.

10. Two Basic Requirements
 The standard used for comparison
purposes must be accurately defined
and should be commonly accepted.
 The apparatus used and the method
adopted must be provable.

11. METHODS OF
MEASUREMENTS
 Direct method
 Indirect method

12. Direct Method
 The unknown quantity (also called the
measurand) is directly compared against
a standard.
 Result is expressed as a numerical
number and a unit. The standard, in fact,
is a physical embodiment of a unit.
 Quite common for the measurement of
physical quantities like length, mass and
time.

13. Drawbacks of direct Method
 Not always possible, feasible and
practicable.
 Most of the cases, are inaccurate
because they involve human factors.
 Less sensitive.
 Hence direct methods are not preferred
and are rarely used.

14. MEASURING SYSTEM
(Indirect Method)
 A measurement system consists of a
transducing element which converts the
quantity to be measured in an
analogous form.
 The analogous signal is then processed
by some intermediate means and is then
fed to the end devices which present the
results of the measurement.

15. INSTRUMENT

16. INSTRUMENT
 An instrument may be defined as a device
for determining the value or magnitude of a
quantity or variable.
 The earliest scientific instruments used the
three essential elements as our modern
instruments do. These elements are
 (i) a detector,
 (ii) an intermediate transfer device, and
 (iii) an indicator, recorder or a storage
device.

18. MECHANICAL
INSTRUMENTS
 These instruments are very reliable for
static and stable conditions.
 But they suffer from a very major
disadvantage. They are unable to
respond rapidly to measurements of
dynamic and transient conditions.

20. ELECTRICAL
INSTRUMENTS
 Electrical methods of indicating the output
of detectors are more rapid than
mechanical methods.
 It is unfortunate that electrical system
normally depends upon a mechanical
meter movement as indicating device.
 This mechanical movement has some
inertia and therefore these instruments
have a limited time (and hence, frequency)
response.

22. ELECTRONIC
INSTRUMENTS
 These instruments require vacuum tubes or
semiconductor devices. Recent practice is to
use semiconductor devices as they have
many advantages over their vacuum tube
counterparts.
 Since in electronic devices, the only
movement involved is that of electrons, the
response time is extremely small on account
of very small inertia of electrons
 example, a C.R.O. is capable of following
dynamic and transient changes of the order of
a few ns (l0-9 s).

23. WORKING OF CRO

24. Absolute Instruments
 These instruments give the magnitude
of the quantity under measurements in
terms of physical constants of the
instrument.
 The examples of this class of
instruments are Tangent Galvanometer
and Rayleigh's current balance.

25. Secondary Instruments
 These instruments are so constructed
that the quantity being measured can
only be measured by observing the
output indicated by the instrument.
 These instruments are calibrated by
comparison with an absolute instrument
or another secondary instrument which
has already been calibrated against an
absolute instrument.
 Examples: Voltmeter, pressure gauge

26. Analog and Digital Instruments
Secondary instruments work in two modes :
(i) Analog mode, and (ii) Digital mode.
 Signals that vary in a continuous fashion and
take on an infinity of values in any given range
are called analog signals. The devices which
produce these signals are called analog
devices.
 In contrast, the signals which vary in discrete
steps and thus take up only finite different
values in a given range are called digital
signals. The devices that produce such
signals are called digital devices.

27. Indicating Instrument
 Instruments and systems use different kinds of
methods for supplying information concerning
the variable quantity under measurement.
 Most of the time this information is obtained as
a deflection of a pointer of a measuring
instrument. In this way the instrument
performs a function which is commonly known
as indicating function.
 For example, the deflection of pointer of a
speedometer indicates the speed of the
automobile at that moment. A pressure gauge
is used for indicating pressure'.

28. Recording Instruments
 In many cases the instrument makes a
written record, usually on paper, of the
value of the quantity under measurement
against time or against some other
variable. Thus the instrument performs a
recording function.
 For example, a potentiometric type of
recorder used for monitoring temperature
records the instantaneous temperatures on
a strip chart recorder.

29. Integrating Instrument
 The integrating instrument measures the
total energy supplied by the circuit in a
given interval of time. It is independent
of the rate at which the total energy
consumed.
 The watt hour meter is the example of
integrating instruments. This type of
meter directly measures the energy in
watt hour.