Upload
rajesh-nelavala
View
62
Download
2
Tags:
Embed Size (px)
DESCRIPTION
mnBASJFBJHSDBCLKJBSDKJVCBSDKVBKJSDBVKJSDBVKJSDVV
Citation preview
5/22/2018 Chapter 6 Gamal
1/25
TRANSDUCERS
Dr. Gamal Sowilam
1
5/22/2018 Chapter 6 Gamal
2/25
IntroductionInput device
Output device
measurement and delivers a proportional electrical
.
The signal is amplified, filtered, or modified to an
.
The output device will display and record the
2
.
5/22/2018 Chapter 6 Gamal
3/25
Introduction (contd)
nonelectrical.
electrical signal in order to use electrical methods and
, , .
A transducer is a device actuated by energy in one
form or in another form to a second transmission
s stem.
3
5/22/2018 Chapter 6 Gamal
4/25
Types of Transducerelectrical principles involved:
Self-Generating Transducers
electrical parameter which can be measured as a
Self-Generating transducers produce an analog
form of energy. They do not require external power.
4
5/22/2018 Chapter 6 Gamal
5/25
Ex: Potentiometric device, Resistance strain gage, thermistor
and photoconductive cell.
Capacitance Transducer
Ex: Variable capacitance pressure gauge, Capacitor
microphone and Dielectric gage. Inductance Transducer
Ex: Magnetic circuit transducer, Differential Transformer and Eddycurrent gage.
Ex: Hall effect pickup, Ionization chamber and Photoemissive
cell.
5
5/22/2018 Chapter 6 Gamal
6/25
-
Application: Temperature, heat flow and radiation.
Application: Velocity and vibration.
Application: Sound, vibration, acceleration and pressure
changes.
Photovoltaic cell
Light meter and solar cell.
6
5/22/2018 Chapter 6 Gamal
7/25
Resistance Transducers
Rotary and slider types of variable resistance
and a variable contact which can be moved along and make
continuous contact with the track. If the track resistance is proportional tothe length along the track
(i.e. linear track), the output voltage will be proportional to the
7
movemen o e var a e con ac an e un s su a e or use as
a position transducer.
5/22/2018 Chapter 6 Gamal
8/25
8
5/22/2018 Chapter 6 Gamal
9/25
9
5/22/2018 Chapter 6 Gamal
10/25
10
5/22/2018 Chapter 6 Gamal
11/25
Inductive Instrumentations
1 Transducer for Linear Position/Force(LVDT)
Consisting of three coils mounted on a
common former and having a magnetic
core that is movable within the coils.
supplied from an A.C. supply and the coilson either side are secondary coils and are
a e e .
Coils A & B have equal number of turns
and are connected in series opposing sothat the output voltage is the difference
between the voltages induced in the coils.
11
5/22/2018 Chapter 6 Gamal
12/25
2. Tachometer
12
5/22/2018 Chapter 6 Gamal
13/25
13
5/22/2018 Chapter 6 Gamal
14/25
.
This transducer used for
fluids that is good connected to
electricity in tubes. The tube is
14
5/22/2018 Chapter 6 Gamal
15/25
Capacitive Instrumentations
This type of instrumentations depends upon on the distance between
15
.
5/22/2018 Chapter 6 Gamal
16/25
1. Rotational movement transducer
2. Linear movement transducer
16
5/22/2018 Chapter 6 Gamal
17/25
3. Pressure transducer
17
5/22/2018 Chapter 6 Gamal
18/25
Temperature TransducerThe temperature Instrumentations can classify into:
. .
2. Thermo Couple.
3. Thermostat.
1. Resistance Thermometer
18
5/22/2018 Chapter 6 Gamal
19/25
19
5/22/2018 Chapter 6 Gamal
20/25
2. Thermocouple
20
5/22/2018 Chapter 6 Gamal
21/25
3. Thermistor
21
5/22/2018 Chapter 6 Gamal
22/25
Temperature Transducer
Platinum RTD (Resistance Temperature Dependent )
Consistin basicall of a thin film of latinum de osited on a ceramic
substrate and having gold contact plates at each end that make contact
with the film. The resistance of the film increases as the temperature increases, i.e. it
has a positive temperature coefficient.
22
5/22/2018 Chapter 6 Gamal
23/25
Transducer for Light Measurement
Photovoltaic Cell
Consisting basically of a two layer silicon device.
When light falls on the junction of the two materials, a voltage is developed with theN-type materia positive wit respect to t e P-type.
The output voltage depends on the magnitude of the light falling on the device and is
a maximum of the order of 0.6 V. With a load resistance connected to the out ut a
23 current will flow.
5/22/2018 Chapter 6 Gamal
24/25
24
5/22/2018 Chapter 6 Gamal
25/25
Piezoelectric Transducer
25