Printed Circuit Boards Glossary:Design,Fabrication and Assembly-L

Logic diagram

A drawing that depicts the multi-state device implementation of logic functions with logic symbols and supplementary notations, showing details of signal flow and control, but not necessarily the point-to-point wiring.

Locating Hole, Locating Notch, Locating Slot

A hole,notch or slot in the panel or printed board to enable it to be positioned accurately during manufacture and/or assembly. Synonyms: fabrication hole (or notch or slot),indexing hole, location hole, manufacturing hole, outrigger hole, tolling hole.

Locating Edge, Locating Hole, Locating Notch, Locating Slot

A physical feature in a panel or printed board used to position the board or mounted components accurately.

 

 

Load Test

A mass re-flow soldering system test for the capacity repeatedly to process boards regardless of their volume though the oven.

Liquids

The lowest temperature at which filler metal (solder) is completely liquid.

Liquation

If a solder alloy with a long melting range is heated too slowly. the phase with the lowest melting point begins to flow first. The material left behind has a changed composition and a higher melting point and will not flow readily. An unsound and unsightly joint is the usual result of liquation.

Line

See Conductor.

Lifted Land

A land that has fully or partially separated (lifted)from the base material, whether or not any resin is lifted with land.

Legend

A format of lettering or symbols on the printed board, e.g. Part number, component locations, and patterns.

Lead Projection

The distance that a component lead protrudes through the side of a board that is opposite from the one upon which the component is mounted.

Lead Mounting Hole

See Component Hole.

Lead

Pronounced “Leed”-A terminal on a component.

LCCC

Leadless ceramic chip carrier.

Layer

One in a series of levels in a board on which tracks are arranged to connect components. Vias connect tracks and zones between layers.

Layer-to-Layer Spacing

 The thickness of dielectric material between adjacent layers of conductive circuitry in a multi-layer printed circuit board.

Laser

Light Amplified by Stimulated Emission of Radiation.

Landless Hole

A plated through-hole without a land(s).

Land

On a PCB, the conductive area(s) to which components are attached. Also called pad.

Land Pattern

A combination of lands that is used to mount, interconnect and test a particular component.

Lamination

The process of manufacturing a laminate; also the process used for application of a dry film photo-resist.

Laminate Presses

Multi-layer equipment that applies both pressure and heat to laminate and prepreg to make multi-layer boards.

Laminate Void

Absence of laminate material in an area which normally contains laminate material.

Laminate Thickness

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

Laminate

A product made by bonding together two or more layers of material.