PCB Glossary

A – D

Activating – the process that makes non-conductive material receptive to electoless layers. Used in plating or finishing PCB.

Additive Process – used in multi-layer boards for plating-through (non-conductive) holes to create vias.

Annular Ring – refers to the circular pad of a drilled hole in a circuit board.

Aperture Information – the D-code list file that contains the specifications of the size and shape of each electronic element on the circuit board.

Array – a group of circuit or element arranged systematically in row or columns.

Aspect Ratio – the parameter ratio that defines the thickness of a circuit board to the diameter of the smallest drilled hole on the same PCB.

Assembly – a combination of electrical and electronic components.

Analog Circuit – An electrical or electronic circuit that produces continuous signal. The counterpart of a digital circuit.

Automated Test Equipment (ATE) – automated equipment that tests functionality and performance of PCBs and other electronic components.

Board Thickness – the thickness of the circuit board. The standard thickness for the base is in the range of 0.059″ to 0.063″.

Built-In Self Test – a testing mechanism that allows electronic devices to test itself

CAD – Stands for Computer Aided Design. These are software tools that help design drafts/plans digitally for engineering, architecture or, electronics circuits, instead of doing the drawings by hand.

CAM – Computer Aided Manufacturing or CAM is an instrumentation software designed for machinery control and automated manufacturing processes

Chip – a miniature form of an integrated circuit embedded on a silicon wafer.

Clearances – refers to the space between the ground/power layer to the plated-through hole in a circuit board. Appropriate clearance should be observed to prevent shorting.

CTE – abbreviation of Coefficient of Thermal Expansion. This refers to the degree of conductive material expansion with changes in temperature.

Daughterboard – refers to the circuit board that is mounted over a consequent board.

Desmear – removal of resin and debris from drilling.

Delamination – refers to the space between the layers of a laminate and metal layer.

Dielectric – An insulator sandwiched by two conductors, example – capacitor.

DIP – abbreviation for Dual In-Line Package, an electronic package with two parallel rows of electrical pins designed for through-hole mounting. Also called DIL-package.

Digitizing – the counter part of analog, its the process of converting analog into discrete quantitative data. In circuit design, it involves digital conversion of a pattern into X-Y coordinates

Dimensional Stability – refers to the stability of a material when exposed to feedback (temperature, chemicals or stress).

Double-Sided Board – refers to a printed board with conductive layer on top and the bottom sides.

Dry-Film Resists – a resistant coating that protects circuit board parts or layers from etching and electroplating damages

Dry-Film Solder Mask – a dry-film type of resistant coating material impregnated to a board via lamination.

DRC – stands for Design Rule Check, a procedure that ensures chip fully layouts satisfy design rules.

Dry Film Resist – or DRF, used in photolithography for pattern formation and is made of multi-layered photosensitive resin.

E – M

Electroless Copper – a layer of copper embedded to the PCB via auto-catalytic processes.

Electroplating – the depostion of adherent coating to a conductive surface.

Edge Connector – the edge of a PCB that has plated lines or holes used to connect to another circuit board or device.

Electronic Component – a part of an electronic circuit packaged simply as a resistor, capacitor, diode, op-amp, logic gates etc.

ENIG – Electroless Nickel Immersion Gold or ENIG is a PCB finishing method that utilizes the auto-catalytic properties of electroless nickel to enable gold attach itself evenly with nickel.

Etchback – refers to removal process of a base material using a chemical emulsion that reacts and exposes the desired pattern on the conductive material of a PCB.

Etching – chemical or electrolytic removal process of unwanted conductive layers on a PCB.

First Article – the sample or protoype of the designed circuit.

Fine Pitch – refers to surface-mount component with lead pitch properties less than or at 25 mils.

Footprint – refers to the size and shape of the pads for soldering certain electronic component.

Functional Test – a standard test program employed to simulate functions of an electronic device.

Gerber File – a file format used to control a photo-plotter and other PCB manufacturing machines.

Ground Plane – the conductive surface in a PCB that has infinite ground potential, referred as the ground point.

IC – stands Integrated Circuit, a miniature electronic circuit that contains both active and passive components.

In-Circuit Test – basic electrical tests for internal circuit values like resistance and capacitance values on individual components.

KGB – abbreviation for Known Good Board, refers to the circuit board that is totally free of any defects. Also known as Golden Board.

Lamination – Many printed circuit boards are made up of multiple layers, these are referred to as multi-layer printed circuit boards. They consist of several thin etched boards or trace layers and are bonded together through the process of lamination.

Leakage Current – a product of a non-perfect capacitor. When the insulator between the conductors of a dielectric is not a perfect non-conducting material, current leaks through it, which results to loss of energy or energy discharge for a capacitor.

Legend – the letters, symbols (ex. R1, C8, etc.) printed on a PCB beside electronic components. These are used as reference to the parts of the PCB design layout.

Major Defect – a defect or malfunctioning component in a circuit that can cause failure of the entire system.

Mask – a lamination that protects board components to enable selective etching or plating.

Measling – refers to white spots at the base laminate, created by the reflection of separated fibers from the glass cloth during weaving.

Microsectioning – a cutting process that prepares the materials for etching, polishing and other metallographic processes.

Microvia – refers to the conductive holes used to connect multilayer circuit boards.

Minimum Conductor Width – the minimum conductor width on a circuit board.

Minimum Conductor Space – the minimum space width between two adjacent conductors.

N – R

Net – the electrical pads to be on the circuit board

Netlist – refers to the list of electrical components and connections in each net in a circuit board.

NPTH – Abbreviation for Non-plated through-hole. Refers to the holes drilled on a circuit board on non-conductive areas.

Pad – the plated area on a circuit board where electronic components are connected.

Pattern – the design layout or configuration of all components in a printed circuit board

Pattern Plating – the plating process where only the conductive pattern layout is applied

Photo Print – the printing process where the circuit pattern image on a board is exposed to light like a photographic film.

Photographic Image – the visible image on a film or photo mask

Photo-plotting – refers to the controlled-light exposure process where an image is produced on a plate/film

PCB – stands for Printed Circuit Board. A silicon wafer board with an embedded layer of conductive material that acts like wires.

Capacitance – the electrical ability of a system to hold charge.

Pin – a metallic or conductive part of the electronic component that is soldered unto the board.

Pitch – the center-to-center spacing between the conductive pads or pins of electronic components.

PTH – stands for plated-through hole, the conductive hole used to interconnect circuit boards

Plotting – the visual pattern conversion of XY coordinates for electronic components and design elements on a circuit board.

Pre-preg – refers the glass fabric sheet with impregnated cured resin

Re-flowing – the initial process where deposited tin or lead is melted and prepared for solidification.

Registration – the standard term on how the plotted circuit board follows the design and layout position of components

Resin Smear – the resin that is embedded to the conductive surface of a drilled hole in a circuit board.

Resist – the laminated material used to coat and protect a printed pattern from exposure to solder and etchants.

Rigid-Flex – refers to the construction of built-in connection on multi-layer flexible circuits.

RoHS – refers to Restriction on Use of Hazardous Substances, a directive where hazardous materials are restricted from manufacturing electrical and electronic components.

Routing (Tracing) – refers to the positioning of electronic connections/components between conductive pads in a circuit board.

S – Z

Screen Printing – refers to the image-transfer process between a stencil screen and a squeegee.

Signal layer – refers to the layers where conductive traces can be laid out.

Silk Screen – refers to the layer of the circuit board where the legends are printed.

Small Outline Integrated Circuit (SOIC) – a type of surface-mounted IC that has the same pin-out layout as of DIP circuits.

SMD – refers to Surface Mount Device, electronic components designed for surface mount technology. SMDs have the advantage of being small and cheap to manufacture, but not generally for prototyping on breadboards.

SMT – stands for Surface Mount Technology, the circuit construction method where components are mounted directly on the board instead of using wire leads on holes.

SMOBC – stands for Solder Mask Over Bare Copper, a process where hot air levels out the solder over copper areas.

Solder – a metal alloy melted and used to connect metal points of electronic parts and the printed circuit board.

Solder Mask – same as solder resist. A resistive material used to prevent the solder alloy from adhering a an applied surface.

SPC – stands for Statistical Process Control, the data collection process used to monitor the functions and stability of the circuit.

Step-And-Repeat – refers to the method where an image goes through successive exposure to produce multiple copies of the original image.

Substrate – a material layer that supports printed circuit elements. A substrate can also be an adhesive layer used for bonding or coating other lamination layers.

Test Coupon – a part of the PCB where printed coupons(contains quality test results) are placed

Test Point – the points in a circuit where functional parameters are tested.

Thief – a term for a cathode placed on a board that regulates the current density that goes through the circuit.

Tooling Holes – refers to the holes drilled in a PCB that is used for manufacturing hold-down.

Twist – a defect in the lamination process that creates uneven or twisted arc on the plane(board).

Thermal Pad – a special pad (usually made of paraffin) used to ease conduction of heat towards the heatsink and away from the electronic components

Through-Hole – the drilled hole in a circuit board where electronic parts are mounted.

Trace – the conductive wiring layout for electrical or electronic connections

UL – stands for Underwriters Laboratories, an electrical device safety standard followed by several underwriters.

UV Curing – refers to process where a resin material coated with ink is polymerized and hardened via UV exposure.

Via – are the through holes used to connect conductors to different layers or sides of a PCB

Void – the space where there are no mounted electronic components or substances.

Wave Soldering – refers to the method of soldering joints simultaneously with a quick wave of molten.

Wicking – refers to the process where copper ions are migrated into the insulating material, typically glass fibers.