Segi Transducer
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Transcript of Segi Transducer
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TRANSDUCER
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TRANSDUCER
Convert variousphysical
quantities intorelated
electrical values
Any device thatconvert oneenergy to
another
In electronic
instrumentationnonelectrical
physicalquantity
electrical signal
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WHY WE NEED
TRANSDUCERS?
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TRANSDUCERS
INDAILY LIFE
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Transducers
inyour daily life
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How does microphone works
Sound waves hit the diaphragm, itcauses the diaphragm to vibrate.
Coils within the magnetic field insidethe microphone starts to vibrates.
Current is generated.
When coil is shorted
current startsto flow in the coil.
Convert sound electrical energy.
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TRANSDUCER FUNCTION
Sense thepresence,
magnitude, changein, and frequency
of some*measurand
Sense
Provide anelectrical output
that givesaccurate
quantitative dataabout *mesurand
Provideoutput
Transducer
MeasurandElectrical
Output
Excitation
Transducers block diagram
*Measurand =
the quantity,property, or
conditiontranslated intoelectrical signal
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TYPES OF TRANSDUCERS
Passive Active/Self Generating
Transducers- Variable resistance
- Variable inductance
- Variable capacitance
- Moving-coil generator
- Thermocouple
- Piezoelectric
- Photovoltaic cell
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HOW TO SELECT ATRANSDUCER?
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ASCERTAIN ON THE FOLLOWINGCRITERIA
Operating range range requirement & goodresolutions
Sensitivity to allow sufficient output
Accuracy to minimize calibration error
Environmental compatibility ensure that theimpact from the environment (i.e. humidity,
extreme hot or cold etc.) does notcompromise the transducer used
Electrical determine the additionalappliances needed
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COMMON TRANSDUCERS
Resistive positiontransducers
Strain gauge
Capacitive transducers
Variable inductancetransducers
Piezoelectrictransducers
Resistancetemperature detectors
Thermocouples
Thermistors
Photoconductive cells
Photodiode
Phototransistor
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Resistive position transducers
VT
R
R
V
Principle the physical variable undermeasurement that causes resistance change in
the sensing element
Basic equations
A
B
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Resistive position transducers
Exercise example:
A displacement transducer with a shaft stroke of 3.0 in.is applied in the circuit of the previous figure. The total
resistance of the potentiometer is 5k, and the appliedvoltage VT = 5.0V. When the wiper is 0.9 in. from B, whatis the value of the output voltage V?
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Resistive position transducersExercise example:
A resistive position transducer with a resistance of 5000and a shaft strokeof 5.0 in. is used in the arrangement of figure below. Potentiometer RRis also5000and VT = 5.0 V. The initial position to be used as a reference point issuch that R= R(i.e. the shaft is at midstroke). At the start of the test,potentiometer RRis adjusted so that the bridge is balanced (V= 0).Assuming that the object being monitored will move a maximum distance of 0.5in. toward A, what will the new value of Vbe? (If the wiper moves 0.5 in.toward A from midstroke, it will be 3.0 in. from B).
R
R
x
VT
VE
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Resistive position transducers
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To be continued in the next
lecture