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PCB Knowledge-1

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Annular Ring
The remaining area of a pad after a hole is drilled through the pad. It is a circular ring of conductive foil and plating material.

AOI
Automated optical inspection.

Aperture
A description of the shape and size of the tool used to create a pad or track. The term comes from the days of vector photo plotters, where film was exposed by shining light through apertures (shaped holes) arrayed around the edge of a disk (or "aperture wheel"). Each aperture corresponded to a different D code in the Gerber data. Today, photoplotters use lasers to expose the film but the term "aperture" persists.

Aperture List / Aperture Table
A list of the shapes and sizes for describing the pads and tracks used to create a layer of a circuit board.

Aspect Ratio
The ratio of the circuit board thickness to the smallest hole diameter.

Bare Board
A finished printed circuit board (PCB) that has no components mounted yet.

Base Laminate
The substrate material upon which the conductive pattern may be formed. The base material can be rigid or flexible.

Blind via
A via hole that does not pass completely through the printed circuit board. A blind via starts from one side or another.

Buried via
A via connects two or more inner layers but no outer layer, and cannot be seen from either side of the board.

CEM1 or CEM3
PCB board materials, standard epoxy resin with woven glass reinforcement over a paper core, differing only in the type of paper used. They are less expensive than FR4

Component Side
The side of a printed circuit board on which most of the components will be mounted.

Double Side PCB
The pads & traces are on both sides of the board.

Electroless Desposition/Plating
The deposition of conductive material from an auto catalytic reduction of a metal ion on certain catalytic surfaces.

Electroplating
The electrodeposition of a metal coating on a conductive object. The object to be plated is placed in an electrolyte and connected to one terminal of a d-c voltage source. The metal to be deposited is similarly immersed and connected to the other terminal. Ions of the metal provide transfer to metal as they make up the current flow between the electrodes.

Etching
Removing unwanted metallic substance by chemical or chemical/electrolytic process.

FR-4
The most commonly used PCB board material. "FR" stands for Flame Retardant and "4" means woven glass reinforced epoxy resin.

Gerber CAM Viewer
There are many Gerber viewers on the market. Here is a short list: GC Prevue, ViewMate, GerbTool, CAM 350, CAMTASTIC, CAMCAD, CAM Expert, Evgraver, ViewPlot.

HASL
Hot air solder levelling

Internal Layer
A conductive pattern which is contained entirely within a multilayer printed board.

Multilayer PCB
The pads and traces are on both sides and also there are traces embedded within the board. Speedy PCB is able to provide 3-20 multi layer boards.

NPTH
NPTH: Non-plated Through Hole.

OSP
Organic Solder Preservative

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

Panel
An array of, usually identical, separate circuits manufactured on the same piece of material.

PCB Design Software/Tools
Software that helps designer to do schematic, layout design, routing and optimizations, etc. There are many desing software and tools in the market. Some of them are free PCB design software. Here is a short list: ExpressPCB, EAGLE, PROTEL, CADSTAR, ORCAD, CIRCUIT MAKER, P-CAD 2000, PCB ELEGANCE, EDWIN, VISUALPC, BPECS32, AUTOENGINEER, EXPERT PCB, CIRCAD, LAYOUT, CIRCUIT LAYOUT, MCCAD, DREAM CAD, E-CAD, POWERPCB, PCB ASSISTANT, PCB DESIGNER, QCAD, QUICK ROUTE, TARGET 3001, WIN CIRCUIT 98, BOARD EDITOR, PCB, VUTRAX, CIRCUIT CREATOR, PADSPCB, DESIGN WORKS, OSMOND PPC, LAY01, SCORE, GElectronic, PRO-Board, PRO-Net , CSIEDA, VISUALPCB, WINBOARD, ULTIBOARD, EASY PC, RANGER, PROTEUS, EPD - Electronics Packaging Designer , AutoTrax Eda, SprintLayout, CADINT, KICAD, Merlin PCB Designer, FREE-PCB, TinyCAD, WINQCAD, Pulsonix, DIPTRACE.

PCB Fabrication Process
A general process can be simplified as: Copper laminate -> Drill board -> Deposit Cu -> Photolithography -> Tin lead plate or finishing -> Etch -> Hot air level -> Solder mask -> E-Testing -> Routing/V-scoring -> Product inspection -> Final cleanning -> Packaging .

PTH
Plated Through Hole, a hole with the plated copper on its sides to provide electrical connections between conductive patterns at the levels of a printed circuit board. There are two types of PTH. One is for mounting components and the other is not used to mount component (see via).

RoHS
Restriction of Hazardous Substances, is one of a handful of European legislation intended to eliminate or severely curtail the use of cadmium, hexavalent chromium, and lead in all products from automobiles to consumer electronics.

RoHS Compliant PCB
PCB boards that are processed under RoHS regulations.

Silkscreen
Colored marks (usually white) on the PCB board to identify components for later assembly and trouble shooting processes. They can be put on either or both sides of the board.

Single Side PCB
The pads and traces are on the one side of the board only.

Surface finish
We provide 5 default surface finishing processes (HASL, OSP, Immersion gold, Immersion silver, Gold plating) for all of regular boards.

Via
A plated through hole (PTH) in a Printed Circuit Board that is used to provide electrical connection between a trace on one layer of the Printed Circuit Board to a trace on another layer. Since it is not used to mount component leads, it is generally a small hole and pad diameter.


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Comments

  1. kabaleevisu's Avatar
    i have doubt in base material what is base material i think base material is copper foil,core and prepreg right ?