The document discusses the key components required for a data acquisition system: sensors/transducers to measure physical variables and convert them to electrical signals, signal conditioning circuitry to prepare the signals for processing, and data acquisition hardware like multiplexers and ADCs to digitize the analog signals for a computer to process, display, store, and transmit the data. It provides examples of common transducers for measuring variables like displacement, temperature, light, and describes strain gauges, piezoelectric transducers, and different types of pressure transducers in more detail.

4. Data acquisition system, in effect, requires integration of:
 Sensor/transducer for measurement of physical variables
 Signal-Conditioner/transmission circuitry, that enables
conversion of signal outputs from transducers to a readable
form for Data Acquisition/interface modules.
 The Data Acquisition Hardware comprising Multiplexer,
Amplifier, A/D Converter, Buffer Memory, etc. to digitise
the analog signals for CPU.
 Computer/CPU to process the digital data for data
processing, display, outputs (control), storage,
transmission, etc.

5. What is transducer?
The device which converts the
physical form of signal into
electrical form.

6. Types of Transducer:-
 Displacement
 Force & Pressure
 Temperature
 Light Sensors
 Others

7.  Strain Measurement
Strain Gauge
Piezoelectric Transducer
 Pressure Measurement
 Gravitational Pressure Transducer
Manometers
 Elastic Pressure Transducer
Diaphragm
Capsule
Bellows
Bourdon Tubes

10. Definition:-
Strain Gauge is a passive, Resistive
transducer which converts the
mechanical elongation and compression
into a resistance change.

12. Construction:-
There are many types of strain
gages. Among them, a universal strain
gage has a structure such that a grid-
shaped sensing element of thin
metallic resistive foil (3 to 6μm thick) is
put on a base of thin plastic film (15 to
16μm thick) and is laminated with a
thin film.

13. Construction:-

14. Construction:-

15. Operating Principal:-

16. Wheatstone Meter Bridge

17. Wheatstone Bridge Using Strain Gauge

19. Construction:-

20. Operating Principal:-
 In capacitive pressure sensor, one of these
metal plates is permitted to move in and
out.
 Capacitance between them changes due to
varying distance between the plates.
 The movable plate is connected to a
diaphragm which senses the pressure and
then expands or compresses accordingly.
 The movement of the diaphragm would
affect the attached metal plate’s position
and capacitance would vary.

22. Construction:-

23. Operating Principal:-
 Piezoelectric crystals develop a potential
difference (i.e. voltage is induced across the
surfaces) whenever they are subjected to any
mechanical pressure.
 Attached to the crystal is a horizontal shaft to
which a diaphragm is connected.
 Whenever the diaphragm senses pressure, it
pushes the shaft down which pressurizes the
crystal and voltage is produced.