Biomedical Engineering Reference
In-Depth Information
Table 2.1 (continued)
Measurand/input
variable
Sensor/transducertechnology
Sensing subsystem mechanism
Applications
Flow
Orifice plate
C. Flow converted to differential
pressure
Flow measurement
Rota meter (turbine)
C-M. Flow to rotation—magnetic
Flow measurement
Vortex
C-C. DC flow to oscillatory
flow—piezoelectric
Sense frequency of oscillations
Magneto inductive flow
M. Magnetic field probe
(generates transverse voltage)
Only for conducting liquids—water, acids
Thermal quantities
Temperature
Thermocouple
C. Peltier effect generates voltage
Process monitoring and control
RTDs
PM. Electrical resistivity
Thermistor
PM. Electrical resistivity
IR pyrometer (non contact type)
D-PM. Lens—bolometer
Measures temperature rise at focal plane
Optical
Binary light intensity
Photoconductors
PM. Resistivity modulation
Outdoor, building lighting controls
Light intensity
Phototransistors
M. Reverse bias photodiode
Stored optical data, CD, DVD, CD-ROM
Optical barcode
Bar code scanners
M-D-M. Scanned laser—filter-pin
diode
Product identification, checkout counters.
Market includes assembled system
Optical image (linear
arrays)
Document scanners
M, D-C. Scanner, lens—
photodiode arrays
Office copiers, image digitization. Market
includes diodes only
Acoustic and vibration quantities
Mechanical vibration
in solids
Piezoelectric vibration sensors
C. Mechanical to electrical
Automotive knock sensors, vibration control
and measurement
Medical diagnosis
Ultrasonic imaging
M-C. Ultrasonic beams used as
probes—detectors
Piezoelectric arrays for density/structural
information
(continued)
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