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PCB Glossary View
www.pcbindex.com/PCB-Forum/PCB-Glossary-View_14.htmlAccep... Test
The tests that determine the acceptability of boards as agreed to by purchaser/vendor.
Accepted Quality Level (AQL)
The maximum number of defects per 100 units that can be considered satisfactory as a process average.
Access Holes
A series of holes in successive layers. Each set has a common centre or axis. The holes of a multi-layer printed board provide access to the surface of the land in one of the layers of the board.
Accuracy
The deviation of the measured or observed value from the accepted reference.
Acrylic Resin
A thermosetting ,transparent resin.
Activating
A chemical treatment for conditioning the surface of non-conductive materials for improved adhesion.
Additive Process
A process for obtaining conductive patterns by the selective deposition of conductive material on a clad or unclad base material.
Adhesion Layers
The metal layer that adheres a barrier metal to a metal land on the surface of an integrated circuit.
Adhesive
A substance such as glue or cement used to fasten objects together. In surface mounting, an epoxy adhesive is used to adhere SMDs to the substrate.
Aging
The change of a property, e.g. solderability, with time.
Air Gap
The non-conductive air space between current carrying conductors such as traces, pads, ground planes, etc.
Algorithm
A procedure for solving a problem, usually mathematical.
Alkyd
A thermosetting resin with good electrical properties used for moulding the bodies of components.
Ambient
The surrounding environment coming into contact with the system or PCB in question.
Analog Circuit
A circuit comprised primarily of individual (discrete) components, such as resistors, capacitors, diodes, transistors, etc. The circuit output is a continuous electrical signal that varies in frequency, amplitude, etc., as a function of the input. The magnitude is represented by physical variables such as voltages, current, resistance, rotation, etc.
Analog Circuit Simulator
A tool used to verify the design (or portions thereof) in the analog domain by applying virtual test signals to a virtual model of the design.
Analog Functional Test
At the board level, various analog test signals are applied to a PCB through a switch to point out current outputs.
Analog In-circuit Test
A system measuring component values on a populated PCB before power is applied.
Anchoring Spur
An extension of a land（like one or two blind paths）on a flexible printed board that extends beneath the cover lay to assist in holding the land to the base material.
Angle of Attack
The angle between the face of the squeegee and the surface of the screen.
Annotation
Text or legend pertinent to a board design; text appears off the board areas and consists of lettering and symbols while legend appears on the boards.
Annular Ring
The width of the conductor surrounding a hole through a printed circuit pad.
ANSI
Acronym for “ American National Standards Institute”, an organization formed by industry and the US Government to develop trade and communication standards.
AOI
Automatic Optical Inspection.
Aperture List
List containing the shapes and dimensions of pads and tracks, etc., to expose on the film in a photoplotter.
AQL
Acceptable Quality Level. The maximum number of defectives likely to exist within a population lot that can be considered to be contractually tolerable.
Aqueous Cleaning
A water-based method that may include neutralizers, saponifiers, surfactants, dispersants and anti-foaming agents.
Arc Resistance
The resistance of a material to the effects of a high voltage, low-current, under prescribed conditions, passing across the surface of the material. The resistance is stated as a measure of the total elapsed time required to form a conductive path of the surface (material carbonized by the arc).
Artwork
An accurately scaled configuration used to produce a master pattern. It is generally prepared at an enlarged scale using various width tapes and special shapes to represent conductors.
Artwork Master
An accurately scaled image of the conductive pattern of a PCB which is used to produce the 1:1 production master. The scale is chosen to provide the necessary degree of accuracy.
ASCII
Acronym for “American Standard Code for Information Interchange”; a seven-bit code that assigns numeric values to letters of the alphabet, the ten decimal digits, punctuation marks and other characters.
Aspect Ratio
The ratio of the circuit board thickness to the smallest hole diameter.
Assembly Drawing
i: A drawing depicting the locations of components, with their reference designators (q.v.), on a printed circuit.
Assembly House
A manufacturing facility for attaching and soldering components to a printed circuit.
Assembly Language
A computer language of brief expressions for translation into a machine language.
ATE
( see Automatic Test Equipment )
Automated Component Insertion
Assembling discrete components to PCBs via electrically controlled equipment.
Automatic Test Equipment
Hardware that automatically analyses functional or static parameters to evaluate performance degradation. It also performs fault isolation.
AWG
American Wire Gauge. A method of specifying wire diameter; the higher the number, the smaller the diameter.
Axial Lead
A lead extending out the end and along the axis of a resistor, capacitor or other axial part rather than from the bottom.
Azeotrope
Two or more polar and non-polar solvents that behave when mixed as a single solvent to remove polar and non-polar contaminants with a boiling point lower than its components.
B&B
Blind and Buried via holes.
Backdriving
An in-circuit test procedure for digital circuitry.
Backpanel (Backplane)
see ”Mother Board”
Bare Board
A PCB having all lines, pads and layers intact but without components installed. An unassembled PCB.
Barrel
The cylinder formed by plating through a drilled hole.
Base Copper
The original, thin copper foil present on one or both sides of a copper clad laminate. During PCB manufacture, part of this base copper will be removed by etching. Conductors on the simplest PCBs consist of base copper only.
Base Laminate
The substrate material upon which the conductive wiring pattern may be formed.
Base Material
The insulating material (either rigid or flexible ) as well as the copper foils bonded on one or both sides. It is a synonym for copper-clad laminate, i.e., the basic raw material for PCB manufacture. This also supports all components after assembly.
Base Material Thickness
The thickness of the base material, excluding metal foil or material deposited on the surface.
Base Solderability
The ease with which a metal or metal alloy surface can be wetted by molten solder under minimum realistic conditions.
Basic Wettability
The ease with which a metal or metal alloy can be wetted by molten solder.
BBT
Bare Board Test.
Bed-of-Nails
A method of PCB testing involving a fixture containing a field of spring-loaded pins that are co-ordinated with strategic points or nodes on the board to which they are brought into contact.
Bellows Contact
A connector contact which is a flat sprint folded to provide a uniform spring rate over the full tolerance range of the mating unit.
BGA
Ball Grid Array. Leadless array packaging technology in which solder balls are mounted to the underside of the package.
Biscuit Frame
An array of circuits on a larger “mother” panel.
Bleeding
A condition in which liquid solder resist or rotation spreads larger than the defined apperture.
Blind Via
A via that reaches only one layer beneath the outer layer on one side of a muti-layer board.
Blister
De-lamination in the form of a localized swelling and separation between any of the Layers of a lamination base material, or between base material and conductive foil or protective coating.
PCB Glossary View
www.pcbindex.com/PCB-Forum/PCB-Glossary-View_14.htmlAccep... Test
The tests that determine the acceptability of boards as agreed to by purchaser/vendor.
Accepted Quality Level (AQL)
The maximum number of defects per 100 units that can be considered satisfactory as a process average.
Access Holes
A series of holes in successive layers. Each set has a common centre or axis. The holes of a multi-layer printed board provide access to the surface of the land in one of the layers of the board.
Accuracy
The deviation of the measured or observed value from the accepted reference.
Acrylic Resin
A thermosetting ,transparent resin.
Activating
A chemical treatment for conditioning the surface of non-conductive materials for improved adhesion.
Additive Process
A process for obtaining conductive patterns by the selective deposition of conductive material on a clad or unclad base material.
Adhesion Layers
The metal layer that adheres a barrier metal to a metal land on the surface of an integrated circuit.
Adhesive
A substance such as glue or cement used to fasten objects together. In surface mounting, an epoxy adhesive is used to adhere SMDs to the substrate.
Aging
The change of a property, e.g. solderability, with time.
Air Gap
The non-conductive air space between current carrying conductors such as traces, pads, ground planes, etc.
Algorithm
A procedure for solving a problem, usually mathematical.
Alkyd
A thermosetting resin with good electrical properties used for moulding the bodies of components.
Ambient
The surrounding environment coming into contact with the system or PCB in question.
Analog Circuit
A circuit comprised primarily of individual (discrete) components, such as resistors, capacitors, diodes, transistors, etc. The circuit output is a continuous electrical signal that varies in frequency, amplitude, etc., as a function of the input. The magnitude is represented by physical variables such as voltages, current, resistance, rotation, etc.
Analog Circuit Simulator
A tool used to verify the design (or portions thereof) in the analog domain by applying virtual test signals to a virtual model of the design.
Analog Functional Test
At the board level, various analog test signals are applied to a PCB through a switch to point out current outputs.
Analog In-circuit Test
A system measuring component values on a populated PCB before power is applied.
Anchoring Spur
An extension of a land（like one or two blind paths）on a flexible printed board that extends beneath the cover lay to assist in holding the land to the base material.
Angle of Attack
The angle between the face of the squeegee and the surface of the screen.
Annotation
Text or legend pertinent to a board design; text appears off the board areas and consists of lettering and symbols while legend appears on the boards.
Annular Ring
The width of the conductor surrounding a hole through a printed circuit pad.
ANSI
Acronym for “ American National Standards Institute”, an organization formed by industry and the US Government to develop trade and communication standards.
AOI
Automatic Optical Inspection.
Aperture List
List containing the shapes and dimensions of pads and tracks, etc., to expose on the film in a photoplotter.
AQL
Acceptable Quality Level. The maximum number of defectives likely to exist within a population lot that can be considered to be contractually tolerable.
Aqueous Cleaning
A water-based method that may include neutralizers, saponifiers, surfactants, dispersants and anti-foaming agents.
Arc Resistance
The resistance of a material to the effects of a high voltage, low-current, under prescribed conditions, passing across the surface of the material. The resistance is stated as a measure of the total elapsed time required to form a conductive path of the surface (material carbonized by the arc).
Artwork
An accurately scaled configuration used to produce a master pattern. It is generally prepared at an enlarged scale using various width tapes and special shapes to represent conductors.
Artwork Master
An accurately scaled image of the conductive pattern of a PCB which is used to produce the 1:1 production master. The scale is chosen to provide the necessary degree of accuracy.
ASCII
Acronym for “American Standard Code for Information Interchange”; a seven-bit code that assigns numeric values to letters of the alphabet, the ten decimal digits, punctuation marks and other characters.
Aspect Ratio
The ratio of the circuit board thickness to the smallest hole diameter.
Assembly Drawing
i: A drawing depicting the locations of components, with their reference designators (q.v.), on a printed circuit.
Assembly House
A manufacturing facility for attaching and soldering components to a printed circuit.
Assembly Language
A computer language of brief expressions for translation into a machine language.
ATE
( see Automatic Test Equipment )
Automated Component Insertion
Assembling discrete components to PCBs via electrically controlled equipment.
Automatic Test Equipment
Hardware that automatically analyses functional or static parameters to evaluate performance degradation. It also performs fault isolation.
AWG
American Wire Gauge. A method of specifying wire diameter; the higher the number, the smaller the diameter.
Axial Lead
A lead extending out the end and along the axis of a resistor, capacitor or other axial part rather than from the bottom.
Azeotrope
Two or more polar and non-polar solvents that behave when mixed as a single solvent to remove polar and non-polar contaminants with a boiling point lower than its components.
B&B
Blind and Buried via holes.
Backdriving
An in-circuit test procedure for digital circuitry.
Backpanel (Backplane)
see ”Mother Board”
Bare Board
A PCB having all lines, pads and layers intact but without components installed. An unassembled PCB.
Barrel
The cylinder formed by plating through a drilled hole.
Base Copper
The original, thin copper foil present on one or both sides of a copper clad laminate. During PCB manufacture, part of this base copper will be removed by etching. Conductors on the simplest PCBs consist of base copper only.
Base Laminate
The substrate material upon which the conductive wiring pattern may be formed.
Base Material
The insulating material (either rigid or flexible ) as well as the copper foils bonded on one or both sides. It is a synonym for copper-clad laminate, i.e., the basic raw material for PCB manufacture. This also supports all components after assembly.
Base Material Thickness
The thickness of the base material, excluding metal foil or material deposited on the surface.
Base Solderability
The ease with which a metal or metal alloy surface can be wetted by molten solder under minimum realistic conditions.
Basic Wettability
The ease with which a metal or metal alloy can be wetted by molten solder.
BBT
Bare Board Test.
Bed-of-Nails
A method of PCB testing involving a fixture containing a field of spring-loaded pins that are co-ordinated with strategic points or nodes on the board to which they are brought into contact.
Bellows Contact
A connector contact which is a flat sprint folded to provide a uniform spring rate over the full tolerance range of the mating unit.
BGA
Ball Grid Array. Leadless array packaging technology in which solder balls are mounted to the underside of the package.
Biscuit Frame
An array of circuits on a larger “mother” panel.
Bleeding
A condition in which liquid solder resist or rotation spreads larger than the defined apperture.
Blind Via
A via that reaches only one layer beneath the outer layer on one side of a muti-layer board.
Blister
De-lamination in the form of a localized swelling and separation between any of the Layers of a lamination base material, or between base material and conductive foil or protective coating.