Calibration Terms – Definitions
A/D : Analog-to digital conversion.
Aberration: An optical phenomenon resulting from the failure of a lens or mirror to produce a good image.
Absolute Pressure: Actual pressure on a confined gas, irrespective of the atmosphere on the outside.
Absolute Temperature: The temperature measured from absolute zero as in the Kelvin and Rankine scales.
Absolute Zero: The lowest temperature theoretically attainable (at which the kinetic energy of atoms and molecules is minimal).
Absorption: (1) Loss of energy traveling through a medium. (2) Internal taking up of one material by another. (3) Transformation of radiant energy into other forms of energy when passing through a material substance.
Acceleration: Rate of change of velocity.
Accommodation: Changes in focus of the crystalline lens to adjust the eye of various object distances.
Accuracy: (1) The closeness of agreement between a test result and the accepted reference value (ISO 5725-1). (2) Closeness of agreement between the result of measurement and a true value of the measurand. Accuracy is a qualitative concept (VIM:1993).
A/D: Analog-to-digital conversion.
Adjustment (of a measuring instrument): The operation of bringing a measuring instrument into a state of performance suitable for its use.
Adsorption: Adhesion of one substance to the surface of another.
Alpha: The current amplification factor when connected in a common base configuration.
Alternating Current (AC): Current which reverses polarity at a uniform frequency.
Altimeter: An instrument that measures the height above ground.
Ambient Temperature: Temperature of the air in the immediate vicinity.
Ammeter: A meter that measures the flow of electrical current in amperes.
Amperes: The basic unit of electric current adopted under the Systeme International d’Unites.
of measurements aimed at providing calibration.
Capillarity: The characteristic of a liquid to be raised or depressed in a tube of small bore. This action is caused by a combination of cohesive, adhesive, and surface tension forces.
Cavitation: Process in which small bubbles are formed and implode violently. This results in aggressive cleaning action in ultrasonic cleaners.
Celsius Temperature Scale: A temperature scale based on mercury in glass thermometer with the freezing point of water defined at 0 degree C and the boiling point of water defined at 100 degree C, both under conditions of normal atmospheric pressure.
Center of Instrument: The intersect point of the vertical, horizontal, and optical axis of a transit or similar instrument when perfectly calibrated.
Certify: Provide evidence for or authorize officially.
Certified Reference Material (CRM): Reference material, by a certificate, one or more of whose property values are certified by a procedure which establishes its traceability to an accurate realization of the unit in which the property values are expressed, and for which each certified value is accompanied by an uncertainty at a stated level of confidence (ISO Guide 30:1992).
Centripetal Force: The inward force on a body moving in a curved path around another body.
CGS System: The common metric system of units (centimeter-gram-second).
Characteristic: A property that helps to differentiate between items of a given population. Note: The differentiation may be either quantitative (by variables) or qualitative (by attributes).
Clinometer: An instrument used by surveyors in order to measure an angle of inclination or elevation.
Coefficient of Linear Expansion: The change in unit length in a solid when its temperature is changed 1 degree.
Coefficient of Volume Expansion: The change in unit volume of a solid when its temperature is changed 1 degree.
Cohesion: The intermolecular force that holds together the molecules in a solid or liquid.
Collimation: The process of aligning the optical axis of optical systems to the reference mechanical axes or surfaces of an instrument, or the adjustment of two or more optical axes with respect to each other.
Collimator: An instrument designed to produce collimated (parallel) rays of light usually equipped with displacement and tilt graticules.
Comparator: An instrument for comparing some measurement with a fixed standard.
Complex Vibration: The combination of two or more sinusoidal vibrations existing simultaneously.
Compound: Two or more substances combined in definite proportions by weight and united chemically.
Condensate: Steam which rises and cools to a liquid.
Conductivity: The transmission of heat or electricity or sound.
Conformity: Fulfillment of specified requirements.
Contacts: Elements used to mechanically make or break an electric circuit.
Continuous Duty: A device able to operate continuously with no off or rest period.
Contract Review: Systematic activities carried out by the supplier before signing the contract to ensure that requirements for quality are adequately defined, free from ambiguity, documented, and can be realized by the supplier.
Contractor: Supplier in a contractual situation
Convection: Transmission of energy or mass in a medium by movement of the medium itself.
Conversion Chart: Must be used to convert a parts per million reading to micromho or vice versa because the ppm scales are non linear and the micromho scales are linear. Because of the curve, there is no set ratio so one must refer to the chart.
Correction: The value added algebraically to the uncorrected result of a measurement to compensate for systematic error.
Corrective Action: Action taken to eliminate the causes of an existing nonconformity defect or other undesirable situation in order to prevent recurrence
Creep: The long term change in dimensional characteristics of a body under load, in an elastic force measurement device. This term refers to the change in reading which occurs when a constant load is applied for a period of time.
Critical Angle: The angle between and at which there is neither refraction or internal reflection.
Critical Size: For fissionable material, the minimum amount of a material which will support a chain reaction.
Cryogenic: The science of refrigeration pertaining to the methods for producing and measuring very low temperatures.
Damping: (1) The prevention of free swinging or vibration by some means, usually friction or resistance. (2) The dissipation of energy with motion or time.
Decay Time: The time required for the trailing edge of a pulse to decrease from 90 percent to 10 percent of its maximum amplitude.
Defect: Nonfulfillment of an intended usage requirement of reasonable expectation, including one concerned with safety.
Degree of Documentation: Extent to which evidence is produced to provide confidence that specified requirements are fulfilled.
Demineralization: Removal of mineral constituents from water.
Deionization: Removal of ionized minerals and salts from a solution by a two phase ion exchange procedure.
Density: The mass per unit volume. CGS unit: gm/cm
DI Water: Deionized water.
Dial Indicator: This is a mechanical lever system used for amplifying small displacements and measuring it be means of a pointer which transverses a graduated dial.
Dialysate Meter: Verifies the total concentration of ionized salts in dialysate solutions used in hemodialysis or kidney equipment.
Differential Voltmeter: A voltmeter that operates on the potentiometric principle. The unknown voltage is compared to an adjustable calibrated voltage developed within the differential voltmeter.
Differentiating Circuit: A circuit in which the output voltage is proportional to the rate of change of the input voltage.
Diffraction: When light passes sharp edges or goes through narrow slits the rays are deflected and produce fringes of light and dark bands.
Digital Voltmeter: An electronic voltmeter that gives readings in digits.
Diopter: A unit of measurement of the refractive power of a lens which is equal to the reciprocal of the focal length measured in meters.
Direct Current (DC): A current with a constant polarity.
Disposition of nonconformity: Action to be taken to deal with an existing nonconforming entity in order to resolve the nonconformity.
Distortion: Any deviation from the desired waveform.
Double-Pole, Double-Throw (DPDT): A term used to describe a switch or relay output contact form. Two separate switches that operate simultaneously each with a normally open and normally closed contact and a common connector.
Drift: Slow change of a metrological characteristic of a measuring instrument.
Dyne: The unit of force which, when acting upon a mass of 1 gm, will produce an acceleration of 1 cm/sec/sec.
Effective Mass: The mass of a body which is being acted upon by the buoyant forces of air. The effective mass of a weight is its true mass minus the buoyant force of air displaced by the weight.
Effective Value (RMS): The alternating current value that will produce the same amount of heat in a resistance as the corresponding direct current value.
Efficiency: The ration of useful output energy, usually expressed as a percentage.
Effluent: Liquid that has passed through a processing operation.
Elastic Element: The material of which the transducer is constructed, generally selected for its good elastic properties.
Electrical Relay: Employs a solenoid to provide mechanical action to move a varying number of electrical contacts back and forth or on and off.
Electronic Switch: An electric circuit designed to cause a start and stop action or a switching action.
Electrostatic Field: The region surrounding an electric charge in which another charge experiences a force.
Element: A quality of product, material, or service forming a cohesive entity on which a measurement or observation may be made.
Empirical: Based on actual measurement, observation, or experience without regard to science and theory.
Endoergic Reaction: A reaction which absorbs energy.
ERG: A CGS unit of work or energy.
Error (of measurement): The result of a measurement minus the true value of the measurnand.
Exoergic Reaction: The reaction which liberates energy.
Explosion-Proof (XPRF) Motor: A totally enclosed motor that will withstand an explosion of a specific vapor or gas within its housing, or will prevent sparks or flashes generated within its housing from igniting surrounding vapor or gas.
Factory Calibration: The tuning or altering of a control device by the manufacture to bring it into specification.
Fahrenheit Scale: A temperature scale that defines the freezing point of water as 32 degrees and the boiling point of water a 212 degrees.
Fixed Point: The point where all heat energy applies or removed is used to change the state of a substance.
Flux: (1) A material used to promote fusion or joining of metals in soldering, welding, or smelting. (2) A general term used to designate collectively all the electric or magnetic lines of force in a region.
Force: A push or pull which produces or prevents motion or has a tendency to do so.
Force Measurement Device: Any device which a quantitative determination of an applied force can be made.
Forced Vibration: The motion caused by some mechanical excitation.
Free Vibration: Vibration that occurs without forcing.
Frequency: The number of recurrences of a periodic phenomenon.
Frequency Meter: An instrument for measuring the frequency of an AC signal.
Full Scale Output (FSO): The output at rated capacity minus the output at zero applied force.
Fundamental Method of Measurement: The method of measurement in which the value of a measurand is obtained by measurement of the appropriate base quantities.
Fundamental Mode of Vibration: The lowest natural frequency.
Function Tests: Function test often duplicates unit test activities sincefunction testers do not assume that unit test is adequately done.
Gage: A measuring instrument for measuring and indicating a quantity.
Gage Block: A block of alloy steel with two gaging surfaces.
Gain: Ratio of output voltage, current, or power to input voltage current or power.
Galvanometer: Meter for detecting or comparing or measuring small electric currents.
Gamma Ray: Electromagnetic radiation emitted during radioactive decay and having an extremely short wavelength.
Gas: The state of matter that has no definite shape of volume.
Gauge Factor: The sensitivity of the strain gauge.
Gauge Pressure (psig): A measure of the force per area exerted by a fluid using atmospheric pressure as a zero reference.
Gauss: Unit of magnetic induction.
Go and No-Go Gages: Gages that do not measure actual size but merely determine whether parts are within specified limits.
Grain: A measure of mass in the English gravitational system equal to 1/7000th pound.
Gram: A metric unit of weight equal to one thousandth of a kilogram.
Gram-Atomic Weight: The quantity of an element whose weight in grams is numerically equal to the atomic weight of the element.
Gram-Molecular Weight (Gram-Mole): The relative molecular weight of a compound, expressed in grams.
Graticule: A network of fine lines, dots, cross hairs, or wires in the focal plane of the eyepiece of an optical instrument.
Gravitational Acceleration: The acceleration due to the force of gravity in the product is counted, with respect to a given requirement or set of requirements.
Instability: An undesired change over a period of time, which change is unrelated to input, operating conditions, or load.
Interferometer: Any measuring instrument that uses interference patterns to make accurate measurements of waves.
Interpolation: Calculation of the value of a function
INOP: C1. Inoperative. 2. Slang. Broken.
ISO: International Organization for Standardization.
Inversion: The condition that exists when both axes of an image are reversed.
Inverter: Any mechanical or electrical device for converting direct current into alternating current.
Jitter: Small, rapid variations in a waveform due to mechanical disturbances.
Joule: A unit of electrical energy equal to the work done when a current of one ampere passes through a resistance of one ohm for one second.
Kelvin Temperature Scale: The absolute temperature scale in the CGS system. Kelvin is equal to degrees Celsius plus 273.15.
Kilogram: One thousand grams.
Kinetic Energy: Energy due to motion.
Level: Perpendicular to the force of gravity.
LIMS (Laboratory Information Management System): A system that manages operations of a testing laboratory.
Linearity: The degree to which performance or response approaches the condition of being linear.
Linear Meter: The deflection of the pointer is proportional to the quantity measured.
Load Cell: A type of force transducer designed primarily for the measurement of load or weight.
Loading Effects: An error of measurement resulting in a change of the system under test caused by insertion of the test instrument.
Lumen: Unit of luminous flux.
Magnetic Deflection: Method of bending electrons in a CRT by means of the magnetic field produced by coils placed outside the tube.
Management Review: Formal evaluation by top management of the status and adequacy of the quality system in relation to quality policy and objectives.
Mass: Measure of the quantity of matter that a body contains.
Mass Density: Mass per unit volume.
Mass Number: The number of protons and neutrons in the atomic nucleus of an element.
Mass Unit: A unit of measurement for mass.
Mcleod Gage: A primary instrument for the measurement of pressure in a vacuum system.
Megohm: 1,000,000 ohms of resistivity.
Measurand: A particular quantity subject to measurement.
Measurement: The act or process of measuring.
Measurement Standards: A material measure, measuring instrument, reference material, or system intended to define, conserve, or reproduce a unit or one or more values of a quantity in order to transmit them to other measuring instruments by comparison.
Measurement Uncertainty: The estimated amount by which the measured quantity may depart from the true value.
Measuring Equipment: All of the measuring instruments, measurement standards, reference materials, auxiliary apparatus, and instructions that are necessary to carry out a measurement. This includes measuring equipment used in the course of that used in calibration.
Meter: The basic unit of length adopted under the Systeme International d’Unites (approximately 1.094 yards)
Metrology: The science of measurement.
MEV: The abbreviation for a million electron volts.
MHO: A unit of conductance.
Micro: Equivalence of one millionth.
Micron: A metric unit of length equal to one millionth of a meter.
Milli: Equivalence of one thousandth.
Minute: 1/60th of a degree.
MKS System: The meter-kilogram-second system.
Model for Quality Assurance: Standardized or selected set of quality system requirements situation.
Moment Arm: The length of a torque wrench from the center of pivot to the point where force is applied.
Momentum: The product of the mass of a body and its velocity.
National Institute of Science and Technology: An independent agency of the U.S. Department of Commerce charged with the improvement and maintenance of standards.
Neon: An inert element which is a gas at room temperature.
Neutron: An elementary particle with 0 charge and mass about equal to a proton.
Neutrino: An elementary particle with zero charge and zero mass.
Newton: A unit of force equal to the force that imparts an acceleration of 1 m/sec/sec to a mass of 1 kilogram.
Newtonian Fluid: A fluid whose absolute viscosity is the same for all values of shear stress.
Nominal Value: This is normally the value indicated by the manufacture.
Nonconformity: Nonfulfillment of a specified requirement.
Nonlinear: Pertaining to a response which is not directly or inversely proportional to a given variable.
Normally Closed (NC) Switch: A switch in which the contracts are closed without any external force acting upon it.
Normally Open (NO) Switch: A switch in which contracts are open when no external forces act upon the switch.
Null Method: Any method of measurement in which the reading is taken at zero.
Objective Evidence: Information that can be proved true, based on facts obtained through observation, measurement, tests or other means.
OHM: A unit of electrical resistance equal to the resistance between two points on a conductor when a potential difference of one volt between them produces a current of one ampere.
OHMmeter: A instrument for measuring resistance.
Optical Pyrometer: An instrument designed to estimate the temperature of glowing surfaces.
Optical Tooling: The geometric method of optically establishing a precise line and/or reference plane.
Organization: Company, corporation, firm, enterprise, or institution or part, thereof, whether incorporated or not, public or private, that has its own functions and administration.
Organizational Structure: Responsibilities, authorities, and relationships, arranges in a pattern, through which an organization performs its functions.
Out of Phase: Having waveforms that are of the same frequency but not passing through corresponding values at the same instants.
Out-of-Round: The high and low spots in a true circle.
Overshoot: The initial transient response to an unidirectional change in input which exceeds the steady stat response.
Packing Fraction: The difference between the atomic weight in mass units and the mass number of an element divided by the mass number and multiplied by 10,000.
Parallax: The apparent displacement of an object as seen from two different points that is not on a line with the object.
Parallel Transmission: Transmission of data bits over different lines, as opposed to serial transmission.
Peak-to-Peak Amplitude: The amplitude of an alternating quantity measured from positive to negative peak.
pH: A indication of the acidity or alkalinity of a solution.
PID Control: Control in which the control signal is a linear combination of the error signal, its integral, and its derivative.
Pointer: The needle-shaped rod that moves over the scale of a meter or dial.
Potential: The amount of voltage or change between a point and a zero reference point.
Potential Difference: The difference in potential between any two points in a circuit.
Potential Energy: Energy due to position.
Pontentiometer: A measuring instrument for measuring direct current electromotive forces.
Potentiometric Measurement: Comparing the unknown voltage with a known voltage from a calibrated potentiometer.
Precision: The closeness of agreement between randomly selected individual measurements or test results.
Pressure: Force exerted per unit area.
Preventive Action: Action taken to eliminate the causes of a potential nonconformity defect or other undesirable situation in order to prevent recurrence.
Primary Standard: A unit established by some authority or developed through practical application of a formula.
Probability: A measure of how likely it is that some event will occur.
Proportional Control: Control in which the amount of corrective action is proportional to the amount of error.
Psychrometer: A instrument for measuring relative humidity.
Pyrometer: A device for measuring high temperatures.
Qualification Process: Process of demonstrating whether an entity is capable of fulfilling specified requirements.
Qualified: Status given to an entity when capability of fulfilling specified requirements has been demonstrated.
Quality: The totality of features and characteristics of a product or service that bears on its ability to satisfy given needs.
Quality Assurance: All those planned or systematic action necessary to provide adequate confidence that adequate or service will satisfy given needs.
Quality Audit: A systematic and independent examination to determine whether quality activities and related results comply with planned arrangements and whether these arrangements are implemented effectively and are suitable to achieve objectives.
Quality Audit Observation: Statement of fact during a quality audit and substantiated by objective audience.
Quality Control: The operational techniques and the activities that sustain a quality of product or service that will satisfy given needs; also, the use of such techniques and activities.
Quality Evaluation: Systematic examination of the extent to which an entity is capable of fulfilling specified requirements.
Quality Losses: Losses caused by not realizing the potential of resources in processes and activities.
Quality Management: The totality of functions involved in the determination and achievement of quality.
Quality Manual: Document stating the quality policy and describing the quality system of an organization.
Quality Plan: Document setting out the specific quality practices, resources, and sequence of activities relevant to a particular product, project, or contract.
Quality Policy: Overall intentions and direction of an organization with regard to quality, as formally expressed by top management.
Quality-related costs: Those costs incurred in ensuring satisfactory quality, as well as the losses incurred when satisfactory quality is not achieved.
Quality Surveillance: Continued monitoring and verification of the status of an entity and analysis of records to ensure that specification requirements are being fulfilled.
Quality System: Organizational structure procedures, processes and resources needed to implement quality management.
Requirement for quality: Expression of the needs or their translation into a set of quantitatively or qualitatively stated requirements for the characteristics of an entity to enable its realization and examination.
Radiation: A method of transmission of energy.
Range: (1) Extent of coverage of effectiveness. (2) Measure of distance.
Ratio Bridge: A bridge circuit that uses a calibrated resistive or calibrated inductive voltage divider for one side of the bride.
Reference Line: A line from which all other measurements are taken.
Reference Plane: A reference lie that has been rotated through 360 degrees.
Repeatability: Same reading each time for the same solution.
Resonance: An excited state of a stable particle causing a sharp maximum in the probability of absorption of electromagnetic radiation.
Restoring Force: The constant mechanical force provided.
RHO: The magnitude of the reflection coefficient.
Scale: (1) Something graduated when used as a measure or rule. A series of spaces marked by lines to indicate the magnitude of some quantity. (2) A weighing device.
Scintillation Counter: A device used for the detection of radioactivity.
Secondary Emission: Electron emission that is the direct result of the impact of electrons against a surface.
Seeback Effect: The EMF produced in a circuit containing two contacting conductors of different metals having two junctions at different temperatures.
Sensitivity: Full scale output divided by the rated capacity of a given transducer / load cell.
Sensor: Element of measuring instrument or measuring chain that is directly or indirectly affected by the measurand.
Servo System: A electromechanical system which is used for positioning one element of a system in relation to another.
Shear: A deformation of an object in which parallel planes remain parallel but are shifted in a direction parallel to themselves.
Solenoid Valve: A valve actuated by a solenoid for controlling the flow of gases or liquid in pipes.
Span: Modules of the difference between the two limits of a normal range.
Solid: The state in which a substance has no tendency to flow under moderate stress.
Specifications: The range of values or numerical value which ties the performance of the product parameter.
Spectrum: (1) The entire range of wavelengths within which electromagnetic radiations occur. (2) A segment of wavelengths which has a special function or possesses special properties.
Stability: The ability of a measuring instrument to maintain constant metrological characteristics with time.
Standard: (1) Conforming to or constituting a standard of measurement or value. (2) a basis for comparison. (3) the ideal in terms of which something can be judged
Standard Deviation: A mathematical quantity used to characterize the dispersion of results.
Standard Operating Conditions, standard temperature and pressure (STP): Defined temperature and pressure to which all values are referenced for comparison.
Standard Pressure: The pressure exerted by a column of mercury exactly 760 mm high.
Standard Uncertainty: Uncertainty of the result of a measurement expressed as a standard deviation.
Strain: Deformation of a material body under the action of applied forces.
Straightness: The uniformity of direction throughout the extent of that feature.
Stress: Force that produces strain on a physical body.
Stroboscope: Scientific instrument that provides a flashing light synchronized with the periodic movement of an object.
Subcontractor: Organization that provides a product to the supplier.
Supplier: Organization that provides a product to a customer.
Surface Tension: The tendency of the surface of a liquid to contract.
Tachometer: An instrument for measuring rotational speed in revolutions per minute.
Temperature Coefficient: The change in measured value per unit change in temperature.
Temperature Compensation: The method of reducing the effect of a change in temperature on a force measuring instrument.
Terminal Linearity: Ratio of the actual error voltage in the output to the total input voltage.
Termination: The load connected to the output end of a circuit or transmission line.
Testing: A means of determining the capability of an item to meet specified requirements by subjecting the item to a set of physical, chemical, environmental or operation actions and conditions
Test Instrument: The device being compared with the calibration standard.
Test Line Limit: The pass or fail limit.
Theodolite: A optical instrument used for measuring horizontal or vertical angles.
Thermistor: A semiconductor device made of materials whose resistance varies as a function of temperature.
Tilt Graticule: A graduate reticule used in Collimators for measuring vertical and horizontal tilt, or angular deviation.
Time: Measurement of duration.
Torque: Cause of rotary motion. It is equal to the applied force multiplied by the distance from the center of rotation.
Torr: 1/760 of and atmosphere.
Total quality management: Management approach of an organization, centered on quality based on the participation of its member and aiming at long-term success through customer satisfaction and benefits of all members of the organization and to society.
Traceability: Ability to trace the history, application, or location of an entity by means of recorded identification
Transducer: A device that provides an output quantity having a determined relationship to the force.
Transfer: Standard used as in intermediary to compare standards.
True Mass: Mass as measured in a vacuum.
Uncertainty: A parameter, associated with the result of a measurement that characterizes the dispersion of the values that could reasonably be attributed to the measured.
Unit: A value, quantity, or magnitude of which other values, quantities, or magnitudes are expressed.
Vacuum: Any pressure below atmospheric.
Velocity: The time rate of change of position.
Velocity Constant: The ratio of the velocity of propagation in a transmission line to the velocity of light.
Verification: Confirmation by examination and provision of objective evidence that specified requirements have been filled.
Vibration: Mechanical oscillations or motion about a reference point or equilibrium.
Viscosity: Resistance of a liquid to sheer forces (and hence to flow).
VSLI: Very Large Scale Integration.
Volatile: Readily vaporizable at a relatively low temperature.
Volume: The amount of space which matter occupies.
Wave Front: A surface composed at any instant of all the points just reached by a vibration disturbance in its propagation through a medium.
Weight: The force of gravity acting on an object.