A capacitor which provides a comparatively low impedance ac (alternating current ) around a circuit element.
A heavy trace or conductive metal strip on the printed circuit board used to distribute voltage, grounds, etc., to smaller branch trances.
A conduit, such as a conductor on a printed board, for distributing electrical energy.
A method of testing devices via electrical stress vs temperature and/or time so that units prone to failure are eliminated.
A 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.
A swelling of a printed board that is usually caused by internal de-lamination or separation of fibres.
( 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.
A resin in an intermediate state of cure. The cure is normally completed during the laminating cycle.
A 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.
Solder that spans across two or more conductors causing an electrical short-circuit.
The voltage at which an insulator or dielectric ruptures or at which ionization and conduction take place in a gas or vapour.
A metal alloy (solder) which melts above 450℃ but below metals being joined.
A 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.
The 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’).
A 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.
Patterns that appear in the border area, such as tooling features, test patterns and registration marks.
The duration from hot-bar-heat-up (contact with lead and pad ) until the solder joint is completed.
An adhesive layer used in bonding together other discrete layers of multi-layer printed board during lamination.
The force perpendicular to a board’s surface required to separate two adjacent layers of the board, expressed as force pre unit area.
A failure condition in which a lead is separated from its bonding surface.
The common area between a lead and a land to which it has been terminated.
The portion of an electronic component exclusive of its pins or leads.
The overall thickness of the base material and all conductive materials deposited thereon.
A 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.
An external layer of resin over the reinforcing structure of base material.
Bluetooth 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 ).
A void in the solder fillet caused by outgassing from the barrel of a plated through hole.(see also outgassing )
A 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.
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.
A via that reaches only one layer beneath the outer layer on one side of a muti-layer board.
A condition in which liquid solder resist or rotation spreads larger than the defined apperture.
An array of circuits on a larger “mother” panel.
Ball Grid Array. Leadless array packaging technology in which solder balls are mounted to the underside of the package.
A connector contact which is a flat sprint folded to provide a uniform spring rate over the full tolerance range of the mating unit.
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.
Bare Board Test.
The ease with which a metal or metal alloy can be wetted by molten solder.
The ease with which a metal or metal alloy surface can be wetted by molten solder under minimum realistic conditions.
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.
The substrate material upon which the conductive wiring pattern may be formed.
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.
The cylinder formed by plating through a drilled hole.
A PCB having all lines, pads and layers intact but without components installed. An unassembled PCB.
see ”Mother Board”
An in-circuit test procedure for digital circuitry.
Blind and Buried via holes.
Laminate impregnated with a resin and cured to an intermediate stage (B-stage resin ). Normally designated as prepreg.