| A | Back to Top |
| Absolute Pressures (PSIA) |
Sealed sensor unit which measures pressure relative to an internally sealed vacuum. Typically applications are P0, P3 in aircraft engine applications. Also sometimes used for high pressure such as hydraulic, brake and oxygen pressures. |
| Acceleration Sensitivity
(Error) |
The maximum difference at any measurand value between the
output with and without the application of a specified constant
acceleration along specified axes. Normally specificied in transverse
and perpendicular directions. (% FSO/g) |
| Accuracy |
The ratio of error to Full Scale Output often expressed in
percent of Full Scale output. (%FSO) |
| Acceptor |
A material added as a dopant to a semiconductor to make it
p-type by accept-in valence electrons and leaving holes behind
that can conduct electric charges. Normally Boron is used for
doping Silicon. |
| A/D |
Abbreviation for analog to ditigal |
| A/D converter |
An electronic device used to convert an analog voltage to
a digital signal. |
| Altitude |
The verticle distance above a specified reference datum such
as sea level. |
| Ambient Conditions |
The conditions (Pressure, temperature, etc.) of the device's
environment. |
| Analog Output |
An output of analog voltage derived from processing of digital
and/or analog input to circuitury within an (electronic) device.
Normally a continuous function of the measurand except as modified
by device resolution. |
| Angstrom |
A unit for Ultra-high frequencies equal to ten raised to the
power -10 meters. |
| Annealing |
A heating process that reverse damage to the crystal structure
or to activate dopant. |
| Attitude Error |
The error due to the orientation of the device relative to
direction of the force of gravity on the transducer. |
|
| B | Back to Top |
| Bandwidth |
The highest frequency signal component that can pass through
input amplifiers without being attenuated. |
| Best Fit Straight Line |
A line midway between two parallel straight lines closest
together and enclosing all output points of the instrumentation
between zero load and full scale. |
| Breakdown Voltage Rating |
The voltage (AC or DC) which can be applied across the transducer
insulation without causing arcing or conduction above a specified
current. |
| Bridge Resistance |
Resistance of transducer bridge elements ( input or output
impedance). |
| Burst Pressure Rating |
The pressure which may be applied to the sensing element or
the transducer case just prior to rupture of either. A minimum
number of applications and time duration are also often specified. |
|
| C | Back to Top |
| Calibration |
A test to determine the output signal of the device with a
steady input excitation and known values of the parameter under
controlled conditions |
| Calibration Curve |
A graphical representation of the device output vs. measurand
under controlled conditions. |
| Calibration Cycle |
The application of controlled values of a parameter proving
an output signal over the full range of the instrument in ascending
and descending order. |
| Combined and Hysteresis |
Square of the sums of squares of error due to non-linearity and
that of and Hysteresis non-linearity. |
| Compensated Temperature
Range |
Range of temperatures over which the transducer has been corrected
by the addition of a circuit to correct the output for errors
induced by the change in bridge resistance due to temperature. |
| Compensation |
Addition of supplemental device, circuit, or special materials
to reverse known source of errors. |
|
| D | Back to Top |
| D/A |
Abbreviation for Digital to Analog. |
| D/A Converter |
A device for converting a digital signal to an analog signal. |
| Damping |
An energy absorbing factor that in conjunction with the natural
frequency determines the limit of frequency response and the
response time characteristics of a transducer. In response to
a step function of the parameter a periodic (underdamped) system
oscillates about the voltage level before stabilizing at its
final steady output; an aperiodic (overdamped) system comes
to the final steady output without overshooting; and a critically
damped system is defined as one that is at the point of changing
from a periodic to a aperiodic system. |
| Dead Volume |
Total volume of the pressure port cavity of a transducer with
room barometric pressure applied. |
| Decibel |
A unit of logarithmic measure based on the ratio of power
related quantities such as sound, volts, or watts to a specified
reference in same units. |
| Deposition |
The procedure of deposit materials onto a substrate by means
of vacuum, electrical, screening, or vapor techniques. |
| Dice, Die |
A section of a processed wafer, usually rectangular, which
contains one functional circuit. |
| Dielectric |
An insulating layer. A material that has high resistance. |
| Dielectric Strength |
Same as breakdown voltage. |
| Differential Pressures (PSID) |
The transducer measures the difference between two pressure sources connected to two inlet ports. Differential transducers are used in pressure applications such as across filters. |
| Diffusion |
A process used in semiconductor production by adding small
amounts of impurities or dopants to a semiconductor. |
| Digital Output |
Transducer output that represents the magnitude of the parameter
measured in terms of discrete quantities or codes in a system
of notation. 0 and 1 are commonly used. Digital and analog are
common output types. |
| Donor |
A material added as a dopant to a semiconductor to make it
n-type by donating valence electrons which can conduct electric
charge. An example is phosphorus. |
| Dopant |
A material added in minute quantities to a semiconductor to
alter it's electrical conducting characteristics. They may be
donors or acceptors. |
| Doping |
The process of adding a dopant to semiconductor material. |
| Drift |
A undesired change of a reading with no charge in the input
signal or operating conditions. |
| Dynamic Characteristics |
The characteristics of a transducer which describes its response
to variations in measurand pressure over time. |
|
| E | Back to Top |
| Electrical Connection |
The portion of the transducer assembly used to connect, disconnect,
and reconnect the electrical wiring that carries excitation
voltage, signal or current to and from the transducer. |
| Environmental Conditions |
Specific external conditions, such as shock, vibration, temperature,
moisture, etc. to which a transducer may be exposed during normal
operations. |
| End Point |
Output signal at upper and lower limits of the transducer
range. |
| End Point Line |
Line drawn between the end points of a transducer calibration. |
| Environmental Conditions |
Specified external conditions ,such as shock, vibration, temperature,
moisture, etc. to which a transducer may be exposed during normal
operations. |
| Environmental Conditions,
Operating |
Specified external conditions ,such as shock, vibration, temperature,
moisture, etc. when a transducer is exposed to must perform
as specified. |
| Error |
The mathematical difference between the indicated value and
the true value of the parameter signal. |
| Error Band |
The band of maximum deviations of output values from a specified
reference line or curve due to those causes attributable to
the transducer. Usually described as plus or minus some value
of transducer full scale output. |
| Excitation |
The external electrical voltage and/or current applied to
a sensor assembly to initiate the proportional output. Usually
expressed in ranges the transducer may subjected to without
damage. The value of this voltage is set by calibration and
any serious deviation from this value will negate the calibration. |
| Extrinsic Semiconductor |
A semiconductor that has been doped either n-type or p-type.
Electrons and holes are present in unequal proportions (by 4
to 8 orders of magnitude). |
|
| F | Back to Top |
| Frequency Modulated Output |
An output in the form of frequency deviations from a center
frequency, where the deviation is a function of the measured
parameter. |
| Frequency Output |
An output in the form of frequency which varies as a function
of the applied measurand. |
| Frequency, Natural |
The frequency of free (not forced) oscillations of the sensing
element of a fully assembled transducer. |
| Frequency, Resonant |
The input frequency at which a transducer responds with maximum
output amplitude. If there is more than one frequency the lowest
is the resonant frequency |
| Frequency Response |
The change with frequency of the output/parameter amplitude
ratio( and of the phase difference between the output and the
parameter) for sinusoidal varying measurand applied to a transducer
within a specified range. It is normal consider at plus or minus
3 db and is given by the approximation. F.R.= 1/2pt Freq. Response=
1 divided by 2 times Pi times time constant |
| Full Scale Output |
The value of transducer output at the maximum rated load minus
the output at the minimum rated load. |
|
| G | Back to Top |
| Gage Factor |
A measure of the ratio of the relative change of resistance
to the relative change in length of a resistance strain transducer
(strain gage). |
| Gage Pressures (PSIG) |
The pressure is measured relative to ambient pressure such as oil pressure. Kulite uses a patented dual diaphragm (dual sensor) approach consisting of a first sensor to measure the primary pressure and a secondary sensor to measure the ambient pressure. The outputs are subtracted to give a true gage pressure reading. This approach yields a hermetically sealed vented gage pressure transducer. Typical applications are engine oil, gear box oil and fuel pressures. |
|
| H | Back to Top |
| Hysteresis |
The maximum difference in output, at any measurand value within
the specified range, when the value is approached first with
increasing and then decreasing measurand. Normally expressed
in % FSO. |
|
| I | Back to Top |
| IEEE |
Abbreviation for Institute of Electrical and Electronics Engineers. |
| Input |
Measurand signal (and/or exciting voltage or current). |
| Input Impedance |
The impedance (presented to the excitation source) measured
across the excitation terminals of the transducer. Unless otherwise
specified the impedance is measured at room temperature, etc. |
| Insulation Resistance |
The resistance measured between specified insulated portions
of a transducer when a specified DC voltage is applied at ambient
conditions- room temperature etc. |
| Ion |
The result of an atom losing an electron and becoming positive
or gaining an electron and becoming negative. |
|
| J, K, L | Back to Top |
| Leakage Rate |
The maximum rate at which a fluid is observed or permitted
to leak through a seal. The type of fluid, differential pressure
across the seal, and the direction of flow should be specified.
Units are normally Volume or pressure drop per unit of time. |
| Least Squares Line |
The straight line for which the sum of the squares of the
residuals( deviations) is minimized. |
| Life, Cycle |
The specified number of full and/or partial range excursions
over which a device will operate within specified performance
criteria. |
| Life, Operating |
The length of time over which device will operate to a specified
performance. |
| Life, Storage |
The length of time over which device can be stored at specified
conditions and still operate to a specified performance. |
| Linearity |
The closeness of a calibration curve to a specified straight
line expressed as % FSO. |
| Load Impedance |
The impedance presented to the output terminals of the transducer
by the external circuitry connected to the device. |
|
| M | Back to Top |
| Maximum Ambient Temperature |
The value of the highest (and the lowest) ambient temperatures
that a (Minimum) transducer can be exposed to with or without
excitation applied, without being damaged and subsequently suffering
performance degradation. |
| Maximum Excitation |
Value of excitation voltage or current that can be applied
to the transducer at room conditions without causing damage
or performance degradation. |
| Measurand (Parameter) |
A physical quantity, property, or condition, which is measured,
Sometimes called input, parameter, or variable. |
| Measured Fluid |
The fluid that comes in contact with the sensing element.
Chemical and/or physical properties of this fluid may be specified
to insure proper transducer operation and life. |
| Mounting Error |
An error due to mechanical deformation of the transducer caused
by mounting the device and/or making the electrical connection. |
|
| N | Back to Top |
| Natural Frequency |
See Frequency, Natural |
| Non-Linearity |
See Linearity. Normally expressed as % FSO. |
| Non-Operating Conditions |
Any conditions outside of operating conditions that might
cause transducer to malfunction. |
| Non-Repeatability |
Breakdown of the transducer characteristics of repeatability
a small amount of which is contained in an acceptable error
band. Usually expressed as % FSO. |
| Null |
A
condition, such as of balance, which results in a minimum absolute
value of output. |
|
| O | Back to Top |
| Operation Mode |
A description of how the transducer is used to provide a usable
signal representating a measurand variation. |
| Operating Conditions |
See environmental conditions. |
| Operating Temperature Range |
Temperature range the operating transducer will be subjected
to. |
| Output |
The electrical quantity produced by the transducer which is
a function of the applied measurand. |
| Output Impedance |
The impedance across the output terminals of a transducer
presented by the transducer to the associated external circuitry. |
| Output Noise |
The RMS or peak to peak, as specified, ac component of a transducer's
DC >output in the absence of measurand variations. |
| Output Range |
Design band of output for specified input. |
| Overload |
The maximum value of a measurand that can be applied to a
transducer without damage or change in performance beyond a
specified tolerance. |
| Over Pressure |
See Overload. |
|
| P | Back to Top |
| Pressure Range |
Lowest to the highest pressures to be measured by a specific
transducer. |
| Pressure Media |
See measured fluid. |
| Proof Pressure |
The maximum pressure, which may be applied to the sensing
element without a change in the transducer performance beyond
specified tolerances. Differential pressure transducers must
have the reference pressure specified and whether the reverse
pressure is applicable. |
|
| Q, R | Back to Top |
| Range |
The measurand values over which a transducer is designed to
measure. Indicated by upper and lower values. |
| Rated Electrical Excitation |
The electrical voltage supply the transducer sensing element
for normal operation given the specified output with the application
of a known measurand. |
| Reference Pressure |
The pressure applied to the opposite side of the sensing element-
ambient pressure for gage and perfect vacuum for absolute designs. |
| Reference Pressure Error |
The error in transducer output resulting from errors in the
reference pressure value within a specified reference pressure
range. |
| Reference Pressure Range |
The range of pressures that can be applied to the backside
of a sensing element without changing the pressure transducer's
performance beyond specified tolerances. If no tolerance is
specified, none is allowed. |
| Reference Pressure Sensitivity
Shift |
The sensitivity shift resulting from variations of a differential
pressure transducer's reference pressure within specified limits. |
| Repeatability |
The ability of a transducer to reproduce output values when
the same measurand value is applied repeatedly under the same
conditions and in the same direction. |
| Reproducibility |
See Repeatability |
| Residual Unbalance |
Zero measurand sensing element output |
| Resolution |
The magnitude of output step changes as measurand is continuously
varied over the range. |
| Resonance |
Amplified vibrations of transducer components, within a narrow
frequency band, observable in the output as a vibration applied
along a specific transducer axis. |
| Resonant Frequency |
The input frequency at which a transducer responds with maximum
output amplitude. If there is more than one frequency the lowest
is the resonant frequency |
| Response Time |
The length of time required for the output of a transducer
to rise to a value normally specified as 98 % of the value of
a step change in measurand expressed in milliseconds. |
| Rise Time |
The length of time required for the output of a transducer
to rise from a small specified percentage of it's final value
to a large specified percentage of it's final value as a result
of a step change in the measurand. |
| Room Conditions |
Normal specified ambient conditions. Normally 77 F + or -
18 F, 90 % RH, and 29 + or - 3 in Hg. |
|
| S | Back to Top |
| Sealed Gage Pressures (PSISG) |
The pressure sensor is zeroed at atmosphere pressure. Mostly used in higher pressure applications such as hydraulic pressures. |
| Self-Heating |
Internal heating as a result of electrical energy dissipated
within the transducer. |
| Sensing Element |
The part of the sensing element that responds directly to
the measurand. |
| Sensitivity |
The ratio of the change in transducer output to a change in
the value of the measurand. |
| Sensitivity Shift |
A change in the slope of the calibration curve due to a change
in sensitivity. |
| Sensor |
Instrumentation device, such as transducer. |
| Sound Pressure Level (SPL) |
a unit that is 20 times the logarithm to the base 10 of the
ratio of the pressure of the measured sound to the reference
pressure of 20 micronewtons per square meter. |
| Span |
The algebraic difference between the limits of range. |
| Stability |
The ability of a transducer to retain its performance characteristics
for relatively long period of time. Normally expressed in %
FSO. |
| Static Calibration |
A calibration performed under room conditions and in the absence
of any vibration, shock, or acceleration. |
| Static Error Band |
See Error Band. |
|
| T | Back to Top |
| Temperature Error Band |
The error band applicable to increased or decrease environmental
temperature usually expressed in % FSO/ 100 F. |
| Temperature Range, Compensated |
See Temperature range, operating. Compensated temperature
range is the interval of temperature range that was considered
when designing compensation module for a specific transducer. |
| Temperature Range, Fluid |
The rang for temperatures of the measured fluid, when it is
not the ambient within which operation of the transducer is
intended, and all specific tolerances for the temperature error
band apply. |
| Temperature Range, Operating |
The range of temperatures, given by their extremes, within
which the transducer is designed to operate with no permanent
damage to the transducer. |
Thermal Coefficient of Resistance
(TCR) |
The relative change in resistance of a conductor or semiconductor
per unit change in temperature over a stated range of temperature
normally expressed in ohms per degree F or C. |
| Thermal Compensation |
The addition of circuitry to alter output changed by temperature
error back toward specified values at room temperature. |
| Thermal Sensitivity Shift |
The sensitivity change due to changes of the ambient temperature
from room temperature (design conditions) toward the limits
of the operating temperature range. |
| Thermal Zero Shift |
The zero measurand transducer output shift due to changes
of the ambient temperature from room temperature to the specified
limits of the operating temperature range. |
| Transducer |
A device which provides a usable output in response to a specified
measurand. |
| Transient Response |
The response of a transducer to a step change in measurand.
It is indicated by Time Constant, Ringing Period, and Response
Time. |
| Transverse Acceleration |
An acceleration perpendicular to the sensitive axis of the
transducer. |
|
| U, V | Back to Top |
| Vibration Error |
The maximum change in output, at any measurand value within
the specified range, when vibration levels of specified amplitude
and range of frequencies are applied to the transducer along
specified axes. |
| Vibration Sensitivity |
See Vibration error. |
|
| W, X, Y, Z | Back to Top |
| Warm-up Period |
The period of time required from the time the excitation voltage
is applied to the transducer until the output of the unit is
within the specified tolerances for the applied measurand. |
| Weight |
Weight of the transducer normally not including any portion
that varies such as cables. |
