Indium is a soft, malleable and ductile metal which is generally unaffected by air or water but is soluble in acids.
In Circuit Meter
A meter permanently installed in a circuit; used to monitor circuit operation.
in die
Latin meaning daily.
In Phase
Two periodic waves reaching peaks and going through zero at the same instant are said to be "in phase."
An abbreviation of inches, a secondary unit in the British system of units, now replaced by the SI system and the metre.
Chemical formula for Indium III Oxide.
Chemical formula for Indium III Sulphide.
Chemical formula for Indium III Selenide.
Chemical formula for Indium III Telluride.
Inactive Length
The central portion of a leaf spring that is prevented from flexing by the U-plate.
Chemical formula for Indium Arsenide.
Chemical formula for Indium I Bromide.
Chemical formula for Indium III Bromide.
The emission of light due to heat.
The incentre of a triangle is the center of its inscribed circle.
A secondary unit in the British system of units, now replaced by the SI system and the metre.
Incident Wave
The wave that strikes the surface of a medium.
The circle inscribed in a given figure.
Chemical formula for Indium III Chloride.
A gravity device that measures angular position in degrees.
Included Angle
The angle made by two sides of a polygon.
Included Side
The side between two angles in a polygon.
Foreign particle present as an undesirable impurity in a material.
Inclusive Or
One or the other, or both.
Incomplete Combustion
A combustion reaction or process that does not convert all of the fuel′s carbon and hydrogen into carbon dioxide and water, respectively.
Incomplete Octet
An atom with less than eight electrons in its valence shell.
A nickel based alloy with good corrosion resistance.

Inconel 600
Inconel is a registered trademark of Special Metals Corporation, referring to a family of nickel-based superalloys. Inconel alloys are oxidation and corrosion resistant materials designed for use in high heat environments.

Inconel 625
Inconel is a registered trademark of Special Metals Corporation, referring to a family of nickel-based superalloys. Inconel alloys are oxidation and corrosion resistant materials designed for use in high heat environments.

Inconel 690
Inconel is a registered trademark of Special Metals Corporation, referring to a family of nickel-based superalloys. Inconel alloys are oxidation and corrosion resistant materials designed for use in high heat environments.

Inconel 718
Inconel is a registered trademark of Special Metals Corporation, referring to a family of nickel-based superalloys. Inconel alloys are oxidation and corrosion resistant materials designed for use in high heat environments.

Inconel 939
Inconel is a registered trademark of Special Metals Corporation, referring to a family of nickel-based superalloys. Inconel alloys are oxidation and corrosion resistant materials designed for use in high heat environments.

Inconsistent Linear System
A system of linear equations is inconsistent if it has no solutions.
An unspecified amount, having no exact limits.
Independent Chuck
A chuck in which each jaw may be moved independently of the others.
Independent Events
Two events A and B are independent if the probability that they happen at the same time is the product of the probabilities that each occurs individually.
Independent Suspension
A suspension system that allows each wheel on a vehicle to move up and down independently of the other wheels.
Independent Variable
One that is associated with the inputs to a function.
Index Matching Gel
Material whose index of refraction is almost equal to that of the fibre core and is used to minimize Fresnel reflections.
Index of Absorption
The imaginary part of the complex index of refraction of a medium. Also known as Absorptive Index.
Index of Refraction
This is the ratio of the velocity of light in free space to that in the material.
Index Register
A microprocessor register that holds part of or all the effective address used by an instruction.
Indicated Horsepower
The horsepower developed in the engine cylinder, as calculated from an indicator diagram.
Indicated Mean Effective Pressure
During the cycle of an engine useful work is only done on the power stroke.
Indicated Power
The power developed in the engine cylinder, as calculated from an indicator diagram.
A substance that undergoes a sharp, easily observable change when conditions in its solutions change.
Indicator Diagram
A plot of pressure vs. volume.
Indifferent Electrolyte
Another name for Supporting Electrolyte.
Indirect Titration
Determining the concentration of an analyte by reacting it with a known number of moles of excess reagent.
Indirectly-Heated Tube
A tube in which the filament heats the cathode to produce electron emission.
A soft, malleable and ductile metal which is generally unaffected by air or water but is soluble in acids.
Indium Antimonide


A narrow gap semiconductor material from the III-V group used in infrared detectors, including thermal imaging cameras, FLIR systems, infrared homing missile guidance systems, and in infrared astronomy.

Indium Arsenide


A semiconductor material that has the appearance of grey cubic crystals and is used for construction of infrared detectors.

Indium Gallium Aluminium Nitride


Semiconductor that is the base for blue LEDs.

Indium Gallium Arsenide


Semiconductor used in high-power and high-frequency electronics because of its superior electron velocity with respect to the more common semiconductors silicon and gallium arsenide.

Indium Gallium Nitride
Semiconductor material made from a mix of Gallium Nitride and Indium Nitride.

Indium Gallium Phosphide


Semiconductor composed of indium, gallium and phosphorus used in high-power and high-frequency electronics.

Indium I Bromide


A red crystalline compound made from heating the Indium metal with InBr3.

Indium III Bromide


Hygroscopic yellow-white monoclinic crystals.

Indium III Chloride


Colourless salt finds some use in organic synthesis as a Lewis acid and is also the most available soluble derivative of indium.

Indium III Fluoride


Used in the synthesis on non-oxide glasses.

Indium III Oxide


Used as an n-type semiconductor and as a resistive element in integrated circuits.

Indium III Selenide


Potential for use in photovoltaic devices and it has been the subject of extensive research.

Indium III Sulphate


White-grey odourless powder, hygroscopic.

Indium III Sulphide


The first indium compound ever described.

Indium III Telluride


Forms blue cubic crystals.

Indium Monoarsenide
Alternative name for Indium Arsenide.
Indium Nitride


Small bandgap semiconductor material which has potential application in solar cells and high speed electronics.

Indium Phosphide


A binary semiconductor used in high-power and high-frequency electronics.

Indium Sesquiselenide
Alternative name for Indium III Selenide.
Indium Tin Oxide


Main feature is the combination of electrical conductivity and optical transparency.

Induced Channel MOSFET
A MOSFET in which there is no actual channel between the source and the drain.
Induced Charge
An electrostatic charge produced on an object by the electric field that surrounds a nearby object.
Induced Current
Current that flows as a result of an Induced EMF.
Induced Electromotive Force
Voltage induced in a conductor in a varying magnetic field.
Induced EMF
Abbreviation of Induced Electromotive Force, a voltage induced in a conductor in a varying magnetic field.
Induced Radioactivity
Radioactivity produced in materials, especially metals, exposed to high-energy photons or neutrons.
The property of an electric circuit to store magnetic energy when carrying a current.
Inductance Bridge
An AC bridge circuit used to measure an unknown value of inductance.
The act or process of producing voltage and current by the relative motion of a magnetic field across a conductor.
Induction Brazing
Bonding is produced by the heat obtained from the resistance of the work to the flow of induced electric current and by using a nonferrous filler metal.
Induction Field
The electromagnetic field that is produced about an antenna when current and voltage are present on the same antenna.
Induction Hardening
Quench hardening in which the heat is generated by electrical induction.
Induction Heating
Heating by combined electrical resistance and hysteresis losses induced by subjecting a metal to varying magnetic field surrounding a coil carrying alternating current.
Induction Losses
The losses that occur when the electromagnetic field around a conductor cuts through nearby metallic objects and induces a current into that object.
Induction Motor
The rotor is energized by transformer action from the stator.
Inductive Coupling
Coupling of two coils by means of magnetic lines of force.
Inductive Effect
An inductive effect is the polarization of a chemical bond caused by the polarization of an adjacent bond.
Inductive Load
Load whose voltage and current are out-of-phase.
Inductive Reactance
The opposition to the flow of an alternating current caused by the inductance of a circuit, expressed in ohms.
Inductively Coupled Discharge
A plasma created by applying an oscillating, radiofrequency potential to an inductive coil.
A magnetic device that stores energy in a magnetic field produced by flowing current.
A collision or interaction in which kinetic energy is not conserved.
A relationship between two expressions that are not equal.
Something that lacks a chemical action.
Inert Electrolyte
Another name for Supporting Electrolyte.
Inert Gas
A gas which does not normally combine chemically with other elements.
Inert Pair
Valence electrons in an s orbital penetrate to the nucleus better than electrons in p orbitals, and as a result they′re more tightly bound to the nucleus and less able to participate in bond formation.
Inertance is the ratio of an acceleration-like quantity to a force-like quantity when the arguments of the real (or imaginary) parts of quantities increase linearly with time.
A two-terminal device in which the forces applied at the terminals are equal, opposite, and proportional to relative acceleration between the nodes.
An object's resistance to a change in its velocity.
Inertia Fuel Shutoff
A switch that shuts off the fuel delivery system when activated by predetermined acceleration.
Inertial Confinement
Methods of producing nuclear fusion by compressing a pellet of fuel using a laser, particle beam, or other external driver.
Inertial Force
A fictitious force that arises in accelerating (noninertial) reference systems.
Inertial Impaction
The process whereby a particle moving in a gas stream strikes slowly moving or stationary obstacles or targets directly in its path.
Inertial Mass
An object′s resistance to a change in its velocity.
Inertial Reference System
Any reference system in which the law of inertia (Newton's first law of motion) is valid.
Inferior Mirage
Mirage in which the inverted image is below the normal one.
Inferior Vena Cava
A blood vessel carrying blood to the heart.
Becoming large beyond bound.
Infinite Impulse Response Filter
A commonly used type of digital filter. This recursive structure accepts as inputs digitized samples of the audio signal, and then each output point is computed on the basis of a weighted sum of past output (feedback) terms, as well as past input values.
A variable that approaches zero as a limit.
A reference to a quantity larger than any specific integer.
A substance which is easily set on fire.
Inflammable Air
An old name for Hydrogen.
A point of inflection of a plane curve is a point where the curve has a stationary tangent, at which the tangent is changing from rotating in one direction to rotating in the oppostie direction.
The fluid entering a component.
Information Filtering
System sorts through large volumes of dynamically generated information to present to the user those nuggets of information which are likely to satisfy his or her immediate needs.
Infrared Amplification by Stimulated Emission of Radiation
A device which amplifies in the infrared band.
Infra-Red Radiation
The region of the electromagnetic spectrum adjacent to that of visible light
Infrared Reflow
Technique in which long wavelength light serves as the heat source to reflow solder and form solder joints.
Infrared Sensor
A device that can detect electromagnetic radiation with wavelengths that are greater than the visible radiation.
Infra-Red Spectroscopy
A technique for determining the structure of molecules by observing how infrared radiation is absorbed by a sample.
Acoustic waves below 20Hz are normally inaudible.
Chemical formula for Indium Gallium Aluminium Nitride.
Chemical formula for Indium Gallium Arsenide.
Chemical formula for Indium Gallium Phosphide.
A steel casting that is cast into a mould which when solidified will be rolled in a blooming mill to plates and slabs for sheets.
To take into the lungs by breathing.
Inherently Low Emission Vehicle
Any vehicle that is certified to meet transitional low-emission vehicle standards established by the California Air Resources Board and does not emit any evaporative emissions.
Inherited Error
The error in initial values used in a computation; especially the error introduced from the previous steps in a step-by-step integration.
Abbreviation for inches of mercury, the old imperial measure of pressure when measured using a mercury barometer.
An additive used to retard undesirable chemical action in a product.
Initial Side
The side that the measurement of an angle starts from.
Initial Time-Delay Gap
The time gap between the arrival of the direct sound and the first sound reflected form the surfaces of the room.
A compound required to start a chain reaction.
A line-segment or figure that begins as the beginning geometric shape for a fractal.
A one to one mapping.
Injection Moulding
A manufacturing process in which molten plastic is injected at high pressure into a mould.
A feedwater pump without moving parts that uses steam pressure and the Bernoulli effect to force feedwater into the boiler, even against its pressure.
Inlet and Exhaust Ports
The inlet or exhaust ports allow air to flow into or out of the cylinder head. Run from the manifold face to the valves.
Inlet Cam
The cam that controls the operation of the air inlet valve in a four-stroke engine.
Inlet Manifold
The main pipe that lies alongside the cylinder heads and from which branch pipes take the air charge to the separate cylinders.
Inline Engine
All of the cylinders are aligned and on one side of an aligned crank.
In-Line Filter
A filter assembly in which the inlet, outlet and filter element axes are in a straight line and fitted in the supply or return pipe.
Chemical formula for Indium Nitride.
Inner Dead Centre
Also known as top dead centre.
Inner Diameter
Dimension that defines the inside diameter of a cavity or hole.
Inner Ear
The inner ear is a labyrinth of twisting fluid-filled passages associated with hearing and balance.
Inner Product
The inner or dot product of two vectors is obtained by adding the products of the respective components of the vectors.
Inorganic Material
Substances not derived from living things.


A carbohydrate, though not a classical sugar. It has a taste which has been assayed at half the sweetness of table sugar.

Chemical formula for Indium Phosphide.
The number or value that is entered, for example, into a function machine.
Input Bias Current
The current that flows into the inputs of a circuit.
Input Impedance
The measured resistance and capacitance between the input terminals of a circuit.
Input Offset Current
The difference in the input bias currents of the two inputs of an instrumentation amplifier.
The reception and transmission of information between control devices using discrete connection points.
Chemical formula for Indium Antimonide.
Inscribed Angle
The angle formed by two chords of a curve that meet at the same point on the curve.
Inscribed Polygon
A polygon whose vertices lie on a circle.
Insertion Loss
This may be applied to a silencer or other sound-reducing element, in a specified frequency band, the decrease in sound power level, measured at the location of the receiver, when a sound insulator or a sound attenuator is inserted in the transmission path between the source and the receiver.
Inside Caliper
An instrument used to measure the inside dimension of an object.
The total amount of solar radiation energy received on a given surface area during a given time.
Refers to a substance that does not dissolve in a solvent to any significant degree.
The tendency of some systems to leave their balanced or resting state.
Instant Glue
More formally known as Cyanoacrylate.
Instantaneous Amplitude
The amplitude at any given point along a wave at a specific instant in time.
Instantaneous Speed
The limiting value of the average speed as the time interval becomes infinitesimally small.
Instantaneous Value
The magnitude at any particular instant when a value is continually varying with respect to time.
Institution of Electrical Engineers
The IEE is an innovative international organisation for electronics, electrical, manufacturing and IT professionals, with specifically tailored products, services and qualifications to meet the needs of today′s technology industry.
Lists all Institutions topics in the Encyclopaedia
Institutions Weblinks
Lists all Institutions Weblinks in the Encyclopaedia
A binary code number that directs the control unit of a computer to perform a certain operation.
Instruction Set
The collection of the instruction codes recognized by the control unit of a computer.
Instrument Platform
Any support structure or vehicle that contains instruments used to make quantitative observations and measurements.
Lists all Instrumentation topics in the Encyclopaedia
Instrumentation Amplifier
A circuit whose output voltage with respect to ground is proportional to the difference between the voltages at its two inputs.
Instrumentation Books
Lists all Instrumentation Books in the Encyclopaedia
Instrumentation Weblinks
Lists all Instrumentation Weblinks in the Encyclopaedia
Insulated Gate Bipolar Transistor
A three-terminal power semiconductor device, noted for high efficiency and fast switching.
A material used to prevent the leakage of electricity from a conductor and to provide mechanical spacing or support as protection against accidental contact with the conductor.
Insulation Resistance
The resistance offered by an insulating material to current leakage.
A material that does not allow the passage of electric charge or is a poor conductor of thermal energy.
Intake Stroke
The suction stroke.
A whole number.
Integral Enthalpy of Solution
The heat absorbed or released when a solute is dissolved in a definite amount of solvent.
Integrated Circuit
First proposed by G. W. A. Dunner in 1952.
Integrated Services Digital Network
Commonly known as ISDN, an early high speed internet connection system mainly aimed at business
Integrating ADC
An ADC whose output code represents the average value of the input voltage over a given time interval.
The inverse of differentiation. Mathematical process used in calculus.
A device for accomplishing a numeric approximation of the mathematical process of integration.
Intellectual Property
Referring to protected proprietary information, usually in the form of a patent, a copyright, a trade secret, or a trademark. Often misused to mean many different things.
Intelligent Transportation System
An advanced technology approach to traffic management.
Intensity of Magnetism
This is the magnetic moment per unit volume of a magnet.
Intensity Stereo
A method of exploiting stereo irrelevance or redundancy in stereophonic audio programmes.
Intensive Properties
Properties which are independent of the amount of the substance.
Interaction Energy
The total energy that is caused by an interaction between the objects being considered.
Interaction Space
The region in an electron tube where the electrons interact with an alternating electromagnetic field.
Interaural Cross-Correlation Coefficient
The measure of the difference in the sounds arriving at the two ears of a listener.
Interaural Fluctuation Strength
Phase differences between ears lead to an inferred source location. If this location changes as a function of time this may be inferred as a signal instability.
Interaural Level Difference
In binaural hearing the interaural level difference has an impact on lateralization throughout the frequency spectrum.
Interaural Phase Difference
Coincident with the interaural time delay, varies systematically with source azimuth and wavelength due to distance from source and refraction around the head.
Interaural Time Difference
This is the difference in arrival time of an acoustic signal at each ear.
The point where two lines drawn on a graph cross each other.
Connections between components.
A device which cools a gas between the compressive steps of a multiple stage compressor.
Diffusion of atoms of one metal into another metal.
Interelectrode Capacitance
The capacitance between the electrodes of an electron tube.
Interelectrode Capacity
The internal capacitances existing between the elements of a vacuum tube.
A boundary across which two systems communicate.
Interfacial Tension
The energy per unit area present at the boundary of two immiscible liquids.
The combining of two or more signals results in an interaction called interference.
Interference Filter
A filter which controls the spectral composition of transmitted energy by interference.
Interference Fit
A fit between a hole and a shaft where there is always some interference between the two.
Interference to Noise Ratio
The ratio of the amount of interfering signal power at the input to the final detector of a receiver, to the amount of noise power produced by that receiver, usually expressed in decibels.
An apparatus used to produce and measure interference from two or more coherent wave trains from the same source.
Pertaining to or measured by an interferometer.
The design and use of optical interferometers.
The warm periods between ice age glaciations.
Intergranular Fracture
Fracture of polycrystalline materials by crack propagation along grain boundaries.
Interior of a Circle
The set of points whose distance from the center of the circle is less than that of the radius.
The placing of a sheet of paper between two adjacent layers of metal to facilitate handling and shearing of rectangular sheets, or to prevent sticking or scratching.
Intermediary Metabolism
The enzyme-catalyzed reactions that extract chemical energy from nutrient molecules and utilize it to synthesize perform cell functions.
Intermediate Fluid
A liquid or gas used to transfer heat between two heat exchangers.
Intermediate Frequency
The fixed frequency to which all carrier waves are converted, resulting from the combination of the received signal and a local oscillator signal, in a superheterodyne receiver.
Intermediate Solid Solution
A solid solution or phase having a composition range that does not extend to either of the pure components of the system.
Intermediate Species
Species formed in a reaction consisting of more than one step.
A compound of two metals that has a distinct chemical formula. The bonds in intermetallic compounds are often partly ionic.
Intermittent Duty
A system that is not required to operate continuously.
Intermittent Wind Tunnel
A wind tunnel in which energy is stored, usually as compressed air, and then released suddenly to force a large quantity of air through.
The mixing of two or more signals in a nonlinear element to produce signals at new frequencies which are sums and differences of the input signals or their harmonics.
Intermodulation Distortion
Distortion produced by the interaction of two or more signals. The distortion components are not harmonically related to the original signals.
Intermolecular Forces
Forces between molecules.
Internal Combustion Engine
Any engine, either reciprocating or rotary, in which the fuel is consumed in the interior of the engine rather than outside of the engine.
Internal Energy
A property of a system that can be changed by a flow of work, heat or both.
Internal Force
Forces which hold an object together when external forces or other loads are applied.
Internal Short-Circuit
A short circuit within a component.
Internal Thread
A screw thread which is formed in a hole, such as the thread in a nut.
International Date Line
The line on the Earth, generally located at 180° longitude, that separates two consecutive calendar days.
International Organization for Standardization
An international body that produces world wide industrial standards.
International Phonetic Alphabet
A system of words identifying the letters of the alphabet and numbers. The system was reached through international agreement, and uses words chosen for their ease of pronunciation by people of all language backgrounds.
International System of Units
The international system of units is based on the seven basic units: Mass, Length, Time, Electric current, Temperature, Amount of substance and Luminous intensity.
A vast worldwide network of computers accessible to anyone.
Internet Protocol
A protocol which computers use to communicate with and over the internet.
Internet Protocol Address
A unique number assigned to any computer connected to the internet.
Internet Service Provider
A company which provides a connection to the internet, or internet services.
Small auxiliary poles, placed between main field poles, whose magnetic field opposes the armature field and cancels armature reaction.
Inter-Quartile Range
For a list of numbers this is the upper quartile minus the lower quartile.
Interrupted Quenching
Quenching in which the metal object being quenched is removed from the quenching medium while the object is at a temperature substantially higher than that of the quenching medium.
An efficient method to quickly request a computer′s attention to a particular external event.
Intersecting Planes
Planes that share a line.
Intersection Law
States that if one input to an AND gate is already TRUE, then the output will depend upon the state of the other inputs only.
Intersection of Sets
The intersection of two or more sets is the set of elements that all the sets have in common.
Interstitial Site
Octahedral and tetrahedral open spaces within a close-packed arrangement of atoms or ions in which a cation can fit.
Interstitial Solid Solution
A solid solution wherein relatively small solute atoms occupy interstitial positions between the solvent or host atoms.
Interstitial Void
An opening in a rock or soil that is not occupied by solid matter.
Intramolecular Forces
Forces within molecules. Forces caused by the attraction and repulsion of charged particles.
An Internal network of an organization that uses Internet protocols.
Intrinsic Carrier Density
The density of electrons and holes in an intrinsic semiconductor.
Intrinsic Semiconductor
A semiconductor free of defects or impurities.
A sequence of nucleotides in a gene that is transcribed but not translated.
A substance which swells as a result of heat exposure, thus increasing in volume, and decreasing in density.
Intumescent Mat
Ceramic fibre mat which irreversibly expands after exposed to high temperature.
An alloy of iron and nickel.

Invariant Point
A point on a binary phase diagram at which three phases are in equilibrium.
A person who thinks up new ideas or processes.
Inverse of a Matrix
The matrix B is an inverse for the matrix A if AB = BA = I.
Inverse Proportionality
A relationship in which a quantity is related to the reciprocal of a second quantity.
Inverse Square
A relationship in which a quantity is related to the reciprocal of the square of a second quantity.
Inverse Time Relay
A relay in which the input quantity and operating time are inversely related throughout at least a substantial portion of the performance range.
Inverted or reversed in position or relationship.
Referring to something being upside down.
Inversion Temperature
The temperature above which a gas gains heat in expansion.
To change a physical or logical state to its opposite state.
A circuit in both analogue and digital systems that provides an output that is inverse to the input. Also a circuit that converts DC to AC.
A function, f(x), is invertible if there is a function, g(x), which is its inverse.
Invertible Matrix
A matrix is invertible if it has an inverse.
Investment Casting
Also known as lost wax and precision casting, it is based on the use of a mould that is only used once.
Not viscous, not clinging or sticky, frictionless.
Inviscid Fluid
A perfect fluid.