Measuring instrument
A measuring instrument is a device for measuring a physical quantity. In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of real-world objects and events. Established standard objects and events are used as units, and the process of measurement gives a number relating the item under study and the referenced unit of measurement. Measuring instruments, and formal test methods which define the instrument's use, are the means by which these relations of numbers are obtained. All measuring instruments are subject to varying degrees of instrument error and measurement uncertainty.
These instruments may range from simple objects such as rulers and stopwatches to electron microscopes and particle accelerators. Virtual instrumentation is widely used in the development of modern measuring instruments.
Time
In the past, a common time measuring instrument was the sundial. Today, the usual measuring instruments for time are clocks and watches. For highly accurate measurement of time an atomic clock is used.Stop watches are also used to measure time in some sports.
Energy
Energy is measured by an energy meter. Examples of energy meters include:Electricity meter
An electricity meter measures energy directly in kilowatt hours.Gas meter
A gas meter measures energy indirectly by recording the volume of gas used. This figure can then be converted to a measure of energy by multiplying it by the calorific value of the gas.Power (flux of energy)
A physical system that exchanges energy may be described by the amount of energy exchanged per time-interval, also called power or flux of energy.*
For the ranges of power-values see: Orders of magnitude.
Action
Action describes energy summed up over the time a process lasts. Its dimension is the same as that of an angular momentum.- A phototube provides a voltage measurement which permits the calculation of the quantized action of light. Also see photoelectric effect.
Mechanics
Length (distance)
- Length, distance, or range meter
Area
- Planimeter
Volume
- Buoyant weight
- Overflow trough
- Measuring cup
- Flow measurement devices
- Graduated cylinder
- Pipette
- Eudiometer, pneumatic trough
For the ranges of volume-values see: Orders of magnitude
Mass- or volume flow measurement
- Gas meter
- Mass flow meter
- Metering pump
- Water meter
Speed (flux of length)
- Airspeed indicator
- Radar gun, a Doppler radar device, using the Doppler effect for indirect measurement of velocity.
- LIDAR speed gun
- Speedometer
- Tachometer
- Tachymeter
- Variometer
Acceleration
- Accelerometer
Mass
- Balance
- Automatic checkweighing machines
- Katharometer
- Weighing scales
- Inertial balance
- Mass spectrometers measure the mass-to-charge ratio, not the mass, of ionised particles.
Linear momentum
- Ballistic pendulum
Force (flux of linear momentum)
- Force gauge
- Spring scale
- Strain gauge
- Torsion balance
- Tribometer
Pressure (flux density of linear momentum)
- Anemometer
- Barometer used to measure the atmospheric pressure.
- Manometer see pressure measurement and pressure sensor
- Pitot tube
- Tire-pressure gauge in industry and mobility
Angle
- Circumferentor
- Cross staff
- Goniometer
- Graphometer
- Protractor
- Quadrant
- Reflecting instruments
- *Octant
- *Reflecting circles
- *Sextant
- Theodolite
Angular velocity or rotations per time unit
- Stroboscope
- Tachometer
For the ranges of frequency see: Orders of magnitude
Torque
- Dynamometer
- de Prony brake
- Torque wrench
Orientation in three-dimensional space
Level
- Dumpy level
- Laser line level
- Spirit level
Direction
- Gyroscope
Energy carried by mechanical quantities, mechanical work
- Ballistic pendulum, indirectly by calculation and or gauging
Electricity, electronics and electrical engineering
Electrical charges interact via a field. That field is called electric field.If the charge doesn't move. If the charge moves, thus realizing an electric current, especially in an electrically neutral conductor, that field is called magnetic.
Electricity can be given a quality — a potential. And electricity has a substance-like property, the electric charge.
Energy in elementary electrodynamics is calculated by multiplying the potential by the amount of charge found at that potential: potential times charge.
.
Electric charge
- Electrometer is often used to reconfirm the phenomenon of contact electricity leading to triboelectric sequences.
- Torsion balance used by Coulomb to establish a relation between charges and force, see above.
Electric current (current of charge)
- Ammeter
- Clamp meter
- Galvanometer
- D'Arsonval galvanometer
[Voltage] ([electric potential] difference)
- Oscilloscope allows quantifying time-dependent voltages
- Voltmeter
[Electric resistance], [electrical conductance] (and [electrical conductivity])
- Ohmmeter
- Time-domain reflectometer characterizes and locates faults in metallic cables by runtime measurements of electric signals.
- Wheatstone bridge
[Electric capacitance]
- Capacitance meter
[Electric inductance]
- Inductance meter
Energy carried by electricity or electric energy
- Electric energy meter
- Electricity meter
Power">Power (physics)">Power carried by electricity (current">Electric current">current of energy)
- Wattmeter
[Electric field] (negative [gradient] of electric potential, voltage per length)
- Field mill
[Magnetic field]
- Compass
- Hall effect sensor
- Magnetometer
- Proton magnetometer
- SQUID
Combination instruments
- Multimeter, combines the functions of ammeter, voltmeter and ohmmeter as a minimum.
- LCR meter, combines the functions of ohmmeter, capacitance meter and inductance meter. Also called component bridge due to the bridge circuit method of measurement.
[Thermodynamics]
And a substance-like property, — the entropy; for example: One glowing coal won't heat a pot of water, but a hundred will.
Energy in thermodynamics is calculated by multipying the thermal potential by the amount of entropy found at that potential: temperature times entropy.
Entropy can be created by friction but not annihilated.
[Amount of substance] (or mole number">Mole (unit)">mole number)
- Gas collecting tube gases
[Temperature]
- Electromagnetic spectroscopy
- Galileo thermometer
- Gas thermometer principle: relation between temperature and volume or pressure of a gas.
- *constant pressure gas thermometer
- *constant volume gas thermometer
- Liquid crystal thermometer
- liquid thermometer principle: relation between temperature and volume of a liquid.
- *Alcohol thermometer
- *Mercury-in-glass thermometer
- Pyranometer principle: solar radiation flux density relates to surface temperature
- Pyrometers principle: temperature dependence of spectral intensity of light, i.e. the color of the light relates to the temperature of its source, range: from about −50 °C to +4000 °C, note: measurement of thermal radiation means: no physical contact becomes necessary in temperature measurement. Also note: thermal space resolution found in Thermography.
- Resistance thermometer principle: relation between temperature and electrical resistance of metals , range: 10 to 1,000 kelvins, application in physics and industry
- solid thermometer principle: relation between temperature and length of a solid.
- *Bi-metallic strip
- Thermistors principle: relation between temperature and electrical resistance of ceramics or polymers, range: from about 0.01 to 2,000 kelvins
- Thermocouples principle: relation between temperature and voltage of metal junctions, range: from about −200 °C to +1350 °C
- Thermometer
- Thermopile is a set of connected thermocouples
- Triple Point cell used for calibrating thermometers.
Imaging technology
- Thermographic camera uses a microbolometer for detection of heat-radiation.
For the ranges of temperature-values see: Orders of magnitude
[Energy] carried by [entropy] or [thermal energy]
This includes thermal capacitance or temperature coefficient of energy, reaction energy, heat flow...Calorimeters are called passive if gauged to measure emerging energy carried by entropy, for example from chemical reactions. Calorimeters are called active or heated if they heat the sample, or reformulated: if they are gauged to fill the sample with a defined amount of entropy.
- Actinometer measures the heating power of radiation.
- constant-temperature calorimeter, phase change calorimeter for example an ice calorimeter or any other calorimeter observing a phase change or using a gauged phase change for heat measurement.
- constant-volume calorimeter, also called bomb calorimeter
- constant-pressure calorimeter, enthalpy-meter or coffee cup calorimeter
- Differential Scanning Calorimeter
- Reaction calorimeter
Entropy
Entropy transfer
Phase change calorimeter's energy value divided by absolute temperature give the entropy exchanged. Phase changes produce no entropy and therefore offer themselves as an entropy measurement concept. Thus entropy values occur indirectly by processing energy measurements at defined temperatures, without producing entropy.- constant-temperature calorimeter, phase change calorimeter
- Heat flux sensor uses thermopiles which are connected thermocouples to determine current density or flux of entropy.
Entropy content
- constant-pressure calorimeter, enthalpy-meter, active
- constant-temperature calorimeter, phase change calorimeter, active
Entropy production
Either the produced entropy or heat are measured or the transferred energy of the non-thermal carrier may be measured.
- calorimeter
Entropy lowering its temperature—without losing energy—produces entropy.
- calorimeter
[temperature coefficient of energy] or "[heat capacity]"
- constant-volume calorimeter, bomb calorimeter
- constant-pressure calorimeter, enthalpy-meter
specific [temperature coefficient of energy] or "[specific heat]"
For the ranges of specific heat capacities see: Orders of magnitude
[Coefficient of thermal expansion]
- Dilatometer
- Strain gauge
Melting temperature">Melting point">Melting temperature (of a solid)
- Thiele tube
- Kofler bench
- Differential Scanning Calorimeter gives melting point and enthalpy of fusion.
Boiling temperature">Boiling point">Boiling temperature (of a liquid)
- Ebullioscope a device for measuring the boiling point of a liquid. This device is also part of a method that uses the effect of boiling point elevation for calculating the molecular mass of a solvent.
More on [continuum mechanics]
This includes mostly instruments which measure macroscopic properties of matter: In the fields of solid state physics; in condensed matter physics which considers solids, liquids and in-betweens exhibiting for example viscoelastic behavior. Furthermore, fluid mechanics, where liquids, gases, plasmas and in-betweens like supercritical fluids are studied.[Density]
This refers to particle density of fluids and compact solids like crystals, in contrast to bulk density of grainy or porous solids.- Aerometer liquids
- Dasymeter gases
- Gas collecting tube gases
- Hydrometer liquids
- Pycnometer liquids
- Resonant frequency and Damping Analyser solids
[Hardness] of a solid
- Durometer
Shape and surface of a solid
- Holographic interferometer
- Laser produced speckle pattern analysed.
- Resonant frequency and Damping Analyser
- Tribometer
Deformation">Deformation (engineering)">Deformation of condensed matter
- Strain gauge all below
Elasticity">Elasticity (physics)">Elasticity of a solid ([elastic moduli])
- resonant frequency and Damping Analyser, using the impulse excitation technique: A small mechanical impulse causes the sample to vibrate. The vibration depends on elastic properties, density, geometry and inner structures.
Plasticity">Plasticity (physics)">Plasticity of a solid
- Cam plastometer
- Plastometer
[Tensile strength], [ductility] or [malleability] of a solid
- Universal Testing Machine
[Granularity] of a solid or of a suspension">Suspension (chemistry)">suspension
- Grindometer
[Viscosity] of a fluid
- Rheometer
- Viscometer
[Optical activity]
- Polarimeter
[Surface tension] of liquids
- Tensiometer
Imaging technology
- Tomograph, device and method for non-destructive analysis of multiple measurements done on a geometric object, for producing 2- or 3-dimensional images, representing the inner structure of that geometric object.
- Wind tunnel
More on electric properties of [condensed matter], [gas]
[Permittivity], [relative static permittivity], ([dielectric constant]) or [electric susceptibility]
- Capacitor
[Magnetic susceptibility] or [magnetization]
- Gouy balance
See also the :Category:Electric and magnetic fields in matter
[Substance potential] or [chemical potential] or molar [Gibbs energy]
conversions like changes of aggregate state, chemical reactions or nuclear reactions transmuting substances, from reactants to products, or diffusion through membranes have an overall energy balance. Especially at constant pressure and constant temperature molar energy balances define the notion of a substance potential or chemical potential or molar Gibbs energy, which gives the energetic information about whether the process is possible or not - in a closed system.Energy balances that include entropy consist of two parts: A balance that accounts for the changed entropy content of the substances. And another one that accounts for the energy freed or taken by that reaction itself, the Gibbs energy change. The sum of reaction energy and energy associated to the change of entropy content is also called enthalpy. Often the whole enthalpy is carried by entropy and thus measurable calorimetrically.
For standard conditions in chemical reactions either molar entropy content and molar Gibbs energy with respect to some chosen zero point are tabulated. Or molar entropy content and molar enthalpy with respect to some chosen zero are tabulated.
The substance potential of a redox reaction is usually determined electrochemically current-free using reversible cells.
- Redox electrode
See also the article on electrochemistry.
Sub-microstructural">Microstructure">microstructural properties of [condensed matter], [gas]
- Infrared spectroscopy
- Neutron detector
- Radio frequency spectrometers for Nuclear magnetic resonance and for Electron paramagnetic resonance
- Raman spectroscopy
[Crystal structure]
- An X-ray tube, a sample scattering the X-rays and a photographic plate to detect them. This constellation forms the scattering instrument used by X-ray crystallography for investigating crystal structures of samples. Amorphous solids lack a distinct pattern and are identifyable thereby.
Imaging technology, [Microscope]
- Electron microscope
- *Transmission electron microscope
- Optical microscope uses reflectiveness or refractiveness of light to produce an image.
- Scanning acoustic microscope
- Scanning probe microscope
- *Atomic force microscope
- *Scanning electron microscope
- *Scanning tunneling microscope
- Focus variation
- X-ray microscope
Rays ("[wave]s" and "particles">Subatomic particle">particles")
Sound, compression waves in matter
s in general, sometimes their sensitivity is increased by the reflection- and concentration principle realized in acoustic mirrors.- Laser microphone
- Seismometer
[Sound pressure]
- Microphone or hydrophone properly gauged
- Shock tube
- Sound level meter
Light and radiation without a [rest mass], non-ionizing">Non-ionizing radiation">non-ionizing
- Antenna
- Bolometer measuring the energy of incident electromagnetic radiation.
- Camera
- EMF meter
- Interferometer used in the wide field of Interferometry
- Optical power meter
- Microwave power meter
- Photographic plate
- Photomultiplier
- Phototube
- Radio telescope
- Spectrometer
- T-ray detectors
[Photon polarization]
- Polarizer
[Pressure] ([current density] of linear momentum)
- Nichols radiometer
[Radiant flux]
- Integrating sphere for measuring the total radiant flux of a light source
[Radiation] with a [rest mass], [particle radiation]
[Cathode ray]
- Crookes tube
- Cathode ray tube, a phosphor coated anode
[Atom polarization] and [electron polarization]
- Stern–Gerlach experiment
[Ionizing radiation]
Ionizing radiation includes rays of "particles" as well as rays of "waves". Especially X-rays and Gamma rays transfer enough energy in non-thermal, collision processes to separate electron from an atom.Particle and ray [flux]
- Bubble chamber
- Cloud chamber
- Dosimeter, a technical device realizes different working principles.
- Geiger counter
- Microchannel plate detector
- Photographic plate
- Photostimulable phosphors
- Scintillation counter, Lucas cell
- Semiconductor detector
- proportional counter
- ionisation chamber
Identification and content
For identification and content concerning chemical substances see also analytical chemistry especially its List of chemical analysis methods and the List of materials analysis methods.
Substance">Chemical substance">Substance content in [mixtures], substance identification
- Carbon dioxide sensor
- chromatographic device, gas chromatograph separates mixtures of substances. Different velocites of the substance types accomplish the separation.
- Colorimeter
- gas detector
- Gas detector in combination with mass spectrometer,
- mass spectrometer identifies the chemical composition of a sample on the basis of the mass-to-charge ratio of charged particles.
- Nephelometer or turbidimeter
- oxygen sensor
- Refractometer, indirectly by determining the refractive index of a substance.
- Smoke detector
- Ultracentrifuge, separates mixtures of substances. In a force field of a centrifuge, substances of different densities separate.
[pH]: [Concentration] of protons in a solution
- pH meter
- Saturated calomel electrode
[Humidity]
- Hygrometer measures the density of water in air
- Lysimeter measures the balance of water in soil
Human senses">Sense">Human senses and [human body]
Sight">Visual perception">Sight
Brightness: photometry">photometry (optics)">photometry
Photometry is the measurement of light in terms of its perceived brightness to the human eye. Photometric quantities derive from analogous radiometric quantities by weighting the contribution of each wavelength by a luminosity function that models the eye's spectral sensitivity. For the ranges of possible values, see the orders of magnitude in:illuminance,
luminance, and
luminous flux.
- Photometers of various kinds:
- *Lux meter for measuring illuminance, i.e. incident luminous flux per unit area
- *Luminance meter for measuring luminance, i.e. luminous flux per unit area and unit solid angle
- *Light meter, an instrument used to set photographic exposures. It can be either a lux meter or a luminance meter, and is calibrated in photographic units.
- Integrating sphere for collecting the total luminous flux of a light source, which can then be measured by a photometer
- Densitometer for measuring the degree to which a photographic material reflects or transmits light
Color: [colorimetry]
- Tristimulus colorimeter for quantifying colors and calibrating an imaging workflow
Hearing
[Loudness] in [phon]
- Headphone, loudspeaker, sound pressure gauge, for measuring an equal-loudness contour of a human ear.
- Sound level meter calibrated to an equal-loudness contour of the human auditory system behind the human ear.
Smell
- Olfactometer, see also the article about olfaction.
Temperature (sense and body)
[Normal [human body temperature|Body temperature]] or [core temperature]
- Medical thermometer, see also infrared thermometer
[Circulatory system] (mainly [heart] and [blood vessels] for distributing substances fast)
- Electrocardiograph records the electrical activity of the heart
- Glucose meter for obtaining the status of blood sugar.
- Sphygmomanometer, a blood pressure meter used to determine blood pressure in medicine. See also :Category:Blood tests
[Respiratory system] ([lung] and [airway]s controlling the breathing process)
- Spirometer
[Concentration] or [partial pressure] of [carbon dioxide] in the respiratory gases
- Capnograph
[Nervous system] ([nerve]s transmitting and processing information electrically)
- Electroencephalograph records the electrical activity of the brain
[Musculoskeletal system] (muscles and bones for movement)
power">Power (physics)">power, work">Mechanical work">work of [muscles]
- Ergometer
metabolic system">Metabolism">metabolic system
- Body fat meter
[Medical imaging]
- Computed tomography
- Magnetic resonance imaging
- Medical ultrasonography
- Radiology
- Tomograph, device and method for non-destructive analysis of multiple measurements done on a geometric object, for producing 2- or 3-dimensional images, representing the inner structure of that geometric object.
[Meteorology]
See also :Category:Meteorological instrumentation and equipment.[Navigation] and [surveying]
See also :Category:Navigational equipment and :Category:Navigation.See also Surveying instruments.
Astronomy
- Radio antenna
- Telescope
Military
Some instruments, such as telescopes and sea navigation instruments, have had military applications for many centuries. However, the role of instruments in military affairs rose exponentially with the development of technology via applied science, which began in the mid-19th century and has continued through the present day. Military instruments as a class draw on most of the categories of instrument described throughout this article, such as navigation, [|astronomy], optics and imaging, and the kinetics of moving objects. Common abstract themes that unite military instruments are seeing into the distance, seeing in the dark, knowing an object's geographic location, and knowing and controlling a moving object's path and destination. Special features of these instruments may include ease of use, speed, reliability and accuracy.Uncategorized, specialized, or generalized application
- Aktograph measures and records animal activity within an experimental chamber.
- Checkweigher measures precise weight of items in a conveyor line, rejecting under or overweight objects.
- Densitometer measures light transmission through processed photographic film or transparent material or light reflection from a reflective material.
- Force platform measures ground reaction force.
- Gauge A highly precise measurement instrument, also usable to calibrate other instruments of the same kind. Often found in conjunction with defining or applying technical standards.
- Gradiometer any device that measures spatial variations of a physical quantity. For example, as done in gravity gradiometry.
- Parking meter measures time a vehicle is parked at a particular spot, usually with a fee.
- Postage meter measures postage used from a prepaid account.
- S meter measures the signal strength processed by a communications receiver.
- Sensor, hypernym for devices that measure with little interaction, typically used in technical applications.
- Spectroscope is an important tool used by physicists.
- SWR meter check the quality of the match between the antenna and the transmission line.
- Time-domain reflectometer locates faults in metallic cables.
- Universal measuring machine measures geometric locations for inspecting tolerances.