A capacitor which provides a comparatively low impedance ac (alternating current ) around a circuit element.
BusA heavy trace or conductive metal strip on the printed circuit board used to distribute voltage, grounds, etc., to smaller branch trances.
Bus_BarA conduit, such as a conductor on a printed board, for distributing electrical energy.
Burn_inA method of testing devices via electrical stress vs temperature and/or time so that units prone to failure are eliminated.
Buried_ViaA via that does not reach a surface layer on either side of a multi-layer board. The via transcends only inner layers of the board.
BulgeA swelling of a printed board that is usually caused by internal de-lamination or separation of fibres.
B_stage( prepreg ) Partially cured resin ( mostly reinforced with glass cloth ) which will soften under a special range of temperature and which can be used to bond together cured laminate sheets to form a multi-layer board.
B_stage_ResinA resin in an intermediate state of cure. The cure is normally completed during the laminating cycle.
BridgingA condition where excess solder builds up in the air gap between conductors and causes them to short together. Solder bridging generally occurs during the wave soldering process. Bridging is basically short-circuiting of a pad to an adjacent track or pad on a board.
Bridged_JointSolder that spans across two or more conductors causing an electrical short-circuit.
Breakdown_VoltageThe voltage at which an insulator or dielectric ruptures or at which ionization and conduction take place in a gas or vapour.
Brazing_AlloyA metal alloy (solder) which melts above 450℃ but below metals being joined.
Branched_ConductorA conductor which connects electrically two or more leads on a printed board assembly. Some branched conductors, notably ground, support and re-set signal, connect many leads.
BowThe deviation from the flatness of a board characterized by a roughly cylindrical or spherical curvature. If the board is rectangular, its four corners are in the same plane (see also: “twist’).
Boundary_ScanA self-test designed into components at the silicon level, permitting testing via a built-in, four-or-five-pin test bus accessing I/O pins.
Border_DataPatterns that appear in the border area, such as tooling features, test patterns and registration marks.
Bonding_TimeThe duration from hot-bar-heat-up (contact with lead and pad ) until the solder joint is completed.
Bonding_LayerAn adhesive layer used in bonding together other discrete layers of multi-layer printed board during lamination.
Bond_Strength:The force perpendicular to a board’s surface required to separate two adjacent layers of the board, expressed as force pre unit area.
Bond_Lift_offA failure condition in which a lead is separated from its bonding surface.
Bond_InterfaceThe common area between a lead and a land to which it has been terminated.
BodyThe portion of an electronic component exclusive of its pins or leads.
Board_ThicknessThe overall thickness of the base material and all conductive materials deposited thereon.
Board_DensityA measure of the ratio of the area of the board used by parts to the total available area of the board. A board with less than 50 to 60 per cent of the available area should be able to be done single-sided, more than 75 to 80 per cent may have to go to multi-layer.
Blutter_CoatAn external layer of resin over the reinforcing structure of base material.
BluetoothBluetooth is a short-range (up to 10m) 2.4GHz wireless connectivity standard intended for such applications as wireless personal area networks (PANs). These PANs can be used to exchange data between devices such as cellphones, digital cameras, printers and household appliances at data rates of up to 721 Kbps ( kilo bits per second ).
Blow_HoleA void in the solder fillet caused by outgassing from the barrel of a plated through hole.(see also outgassing )
BlisteringA localized swelling and separation between any of the layers of a laminated base material, or between base material and conductive foil. It is a form of de-lamination. Also separation of solder mask layer and conductive pattern.
BlisterDe-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.
Blind_ViaA via that reaches only one layer beneath the outer layer on one side of a muti-layer board.
BleedingA condition in which liquid solder resist or rotation spreads larger than the defined apperture.
Biscuit_FrameAn array of circuits on a larger “mother” panel.
BGABall Grid Array. Leadless array packaging technology in which solder balls are mounted to the underside of the package.
Bellows_ContactA connector contact which is a flat sprint folded to provide a uniform spring rate over the full tolerance range of the mating unit.
Base_of_NailsA 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.
BBTBare Board Test.
Base_WettabilityThe ease with which a metal or metal alloy can be wetted by molten solder.
Base_SolderabilityThe ease with which a metal or metal alloy surface can be wetted by molten solder under minimum realistic conditions.
Base_Material_ThicknessThe thickness of the base material, excluding metal foil or material deposited on the surface.
Base_LaminateThe substrate material upon which the conductive wiring pattern may be formed.
Base_MaterialThe 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_CopperThe 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.
BarrelThe cylinder formed by plating through a drilled hole.
Bare_BoardA PCB having all lines, pads and layers intact but without components installed. An unassembled PCB.
Backpanel_(Backplane)see ”Mother Board”
BackdrivingAn in-circuit test procedure for digital circuitry.
B&BBlind and Buried via holes.
B_stage_MaterialLaminate impregnated with a resin and cured to an intermediate stage (B-stage resin ). Normally designated as prepreg.