Title: Md. Bashir Uddin
1Transducer for Physical Parameters
Presented by- Md. Bashir Uddin Roll
1215502 Dept. of BME KUET, Khulna-9203
2Transducers
- A transducer is a device that changes one form of
energy into another. - Sound
Electric signal - Electric signal
Sound
Microphone
Speaker
- A transducer is placed at the input of a
measurement system.
3Physiological Transducer
- A physiological transducer is a device that
changes physiological variables into electrical
signal.
Transducer
Physiological variable
Electrical Signal
Block diagram of physiological transducer
- A variable associated with the physiological
process of the body is called Physiological
variable
4Different forms of Physiological variables
- Ionic potentials currents
- Mechanical movements
- Hydraulic pressure flow
- Temperature
- Chemical reaction and many more
5Transducer energy conversion
- Electrical
- Electro-mechanical
- Electromagnetic
- Photonic
- Photovoltaic, or any other form of energy.
6Construction of Transducer
- Transducer consists of 2 parts-
- Sensing or detector element
- Transduction element
- Sensing or detector element senses or responses
to physical phenomena or change in a physical
object/body. - Transduction element transforms the output of
sensing to an electrical output.
7Performance Characteristics of Transducer
- Accuracy
- Sensitivity
- Threshold
- Noise
- Linearity
8Classification of Transducer
- 5 categories
- Based on principal of transduction
- Primary or Secondary
- Passive or Active
- Analog or Digital
- Transducer and Inverse Transducer
9Based on Principle of Transduction
- Thermo electric
- Magneto resistive
- Electro kinetic
- Optical
- Resistive
- Inductive
- Capacitive
10Primary or Secondary Transducer
- Bourdon tube acts as a primary transducer which
converts pressure into displacement. - The linear displacement then convert into
electrical voltage by linear variable
differential transformer which acts as a
secondary transducer.
11Active Passive Transducers
- Active Transducer No external power reqd. to
produce I/p. It draws power from input applied. - Example Piezo electric xtal used for
accelartion measurement.
- Passive Transducer External power required for
transduction. So it is externally powered. - Example Resistive (Strain Gauge), Inductive
(LVDT), Capacitive Transducers.
12Analog Digital Transducers
- Analog Transducer Convert I/p quantity into
an analog o/p. Analog o/p is a continuous
function of time. - Example Strain gauge, LVDT, thermocouple
Digital Transducer Converts I/p quantity into an
electrical o/p in the form of pulses. Example
Digital Encoder
13Transducer Inverse Transducer
- Transducer Convert nonelectrical variables into
electrical parameters. - Example Microphone
- Inverse Transducer Converts electrical signal to
physical quantity. - Example Speaker
14Transducer Sensor Outputs
15Transducer for biomedical Application
Physical variable Types of transducer
Force Piezoelectric Unbounded strain gage
Displacement Variable Resistance Variable inductance Variable capacitance Linear Variable differential transducer Mercury strain gage
Velocity Magnetic Indection
Temperature Thermocouple Thermostat
Light Photo voltaic Photo electric
Magnetic field Hall effect
16THANK YOU