PCB glossary G-L

PCB Glossary starting with G

G10: A laminate consisting of woven epoxy-glass cloth impregnated with epoxy resin under pressure and heat. G10 lacks the anti-flammability properties of FR-4. Used mainly for thin circuits such as in watches.

Gerber File: Data file used to control a photo plotter.

GI: The woven glass fiber laminate impregnated with polyimide resin.

Gold Finger: The gold-plated terminal of a card-edge connector. Also see Finger.

Ground: A common reference point for electrical circuits returns, shielding or heat sinking.

Ground Plane: A conductor layer, or portion of a conductor layer, used as a common reference point for circuit returns, shielding or heat sinking.

PCB Glossary starting with H

HASL – (Hot Air Solder Leveling): A method of coating exposed copper with solder by inserting a panel into a bath of molten solder then passing the panel rapidly past jets of hot air.

HDI (High Density Interconnect): Ultra fine-geometry multi layer PCB constructed with conductive surface Microvia connections between layers. These boards also usually include buried and/or blind vias are made by sequential lamination.

HDI: High Density Interconnect.

Header: The portion of a connector assembly which is mounted on a printed circuit.

Hermetic: Airtight sealing of an object.

Hole Breakout: A condition in which a hole is partially surrounded by the land.

Hole Density: The number of holes per unit area on a PCB.

Hole Pattern: The arrangement of all holes in a printed board with respect to a reference point.

PCB Glossary starting with I

IC: Integrated Circuit.

Imaging: The process of transferring electronic data to the photo-plotter, which in turn uses light to transfer a negative image circuitry pattern onto the panel or film.

Immersion Plating: The chemical deposition of a thin metallic coating over certain basis metals that is achieved by a partial displacement of the basis metal.

Impedance: The resistance to the flow of current, represented by an electrical network of combined resistance, capacitance and inductance reaction, in a conductor as seen by an AC source of varying time voltage. The unit of measure is ohms.

In-Circuit Test: Electrical test of individual component or part of the circuit in a PCB assembly instead of testing the whole circuit.

Inclusions: Foreign particles, metallic or nonmetallic, that may be entrapped in an insulating material, conductive layer, plating, base material, or solder connection.

Inkjetting: The dispersal of well-defined ink "dots" onto a PCB. Inkjet equipment uses heat to liquefy a solid ink pellet and change the ink into a liquid, which is then dropped via a nozzle onto the printed surface, where it quickly dries.

Inner-Layers: The internal layers of laminate and metal foil within a multi-layer board.

In-Situ Dynamic Thermal Cycling Stress Testing: In-Situ Dynamic Thermal Cycling Stress Testing is an electronics testing method of exposing products from high to low temperature extremes for several cycles, which identities potential early product failures.

Insulation Resistance: The electrical resistance of an insulating material that is determined under specific conditions between any pair of contacts, conductors, or grounding devices in various combinations.

Integrated Circuits (IC): single, integrated components containing a large number of discreet components, such as transistors and other semiconductor devices, as well as the layering which interconnect all of the semiconductor devices.

Interconnect: specialized, high-precision optical and electrical cable and harness assemblies and connectors utilized in the interconnection of electrical components and assemblies. Various interconnect technologies include single-mode and multi-mode cyber optics, coaxial, ribbon cable, shielded and tight pair, tight twisted pairs, patch cords and molded cables.

Interconnect Stress Test: The IST system is designed to quantify the ability of the total interconnect to withstand the thermal and mechanical strains, from the as manufactured state, until the products reaches the point of interconnect failure.

Interstitial Via Hole: An embedded through-hole with connection of two or more conductor layers in a multilayer_ PCB.

IPC: The Institute for Interconnecting and Packaging Electronic Circuits, the final American authority on how to design and manufacture printed wiring.   In 1999, IPC changed its name from Institute of Interconnecting and Packaging Electronic Circuits to IPC. The new name is accompanied with an identity statement, Association Connecting Electronics Industries.

PCB Glossary starting with J

Jump-Scoring: similar to v-scoring, this is a process that is used when a printed circuit board is pannelized. It allows for a score line to jump over most of the panel border, leaving the border largely intact, and as a result, stronger and more rigid, resulting in a stiffer and stronger assembly panel.

PCB Glossary starting with K

KGB: Known good board or assembly. Also known as a golden board.

PCB Glossary starting with L

Laminate: The plastic material usually reinforced by glass or paper that supports the copper cladding from which circuit traces are created.

Laminate Thickness: Thickness of the metal-clad base material, single or double sided, prior to any subsequent processing.

Laminate Void: An absence of epoxy resin in any cross-sectional area which should normally contain epoxy resin.

Lamination: The process manufacturing a laminate using pressure and heat.

Land: The portion of the conductive pattern on printed circuits designated for the mounting or attachment of components. Also called Pad.

Laser Direct Imaging: Laser Direct Imaging is a process that allows increasing board density through the use of increasingly small and accurate laser technology.

Laser Photo-Plotter: A plotter that uses a laser, which simulates a vector photo-plotter by using software to create a raster image of the individual objects in a CAD database, then plots the image as a series of lines of dots at a very fine resolution. A laser photo-plotter is capable of more accurate and consistent plots than a vector plotter.

Lead: A terminal on a component.

Leakage Current: A small amount of current that flows across a dielectric area between two adjacent conductors.

Legend: A format of lettering or symbols on the printed circuit board; e.g., part number, serial number, component locations and patterns.

Line: A thin conductive area on a PCB surface or internal layer usually composed of lands (to which component leads are connected) and paths (traces). Also known as a “conductor”.

LPI: Liquid Photo-Imageable solder mask that uses photographic imaging to control a thinner mask deposition than the dry film solder mask.