Glossary of Terms

ABS

Acrylonitrile Butadiene Styrene (ABS) is an opaque thermoplastic and amorphous polymer.

Absorption

Loss of electromagnetic energy or dissipation when passing through an object.

AL

Aluminium.

Alloy

A mixture of two or more elements classified by the ingredient with the largest content e.g. copper alloy.

Aperture

A hole, gap or opening in an electronic enclosure where electromagnetic fields may travel.

Arcing

An arc is the luminous current discharge which is produced when strong current leaps across the gap between electrodes or within a circuit.

ATEX

Equipment and protective systems intended for use in potentially hazardous atmospheres.

Attenuation

Loss of transmission signal strength measured in decibels (dB).

Bandwidth

A range of frequencies within a given band, in particular that used for transmitting a signal.

BeCu

Beryllium Copper.  An alloy of beryllium and copper used to form BeCu fingerstrip and other contacts.  BeCu has excellent spring qualities and is frequently used for EMI shielding purposes.

Bi-directional

A gasket that can be wiped from either side without snagging.

Bonded

Connected by compressing, welding or other mechanical means to five a good low impedance electrical path which is not affected by heat or corrosion.

CAD

Computer Aided Design.

Compatability

Two materials that form a stable system with no corrosion when in contact with each other.

Compression

Pressure applied to a material rather than tension.

Compression Set

Percentage of permanent height reduction under load, time and temperature.

Conductivity

A material’s ability to conduct electrical current.

Conformal Coating

A protective chemical coating or polymer film 25-75µm thick (50µm typical) that conforms to circuit board topology. It protects electronic circuits from harsh environments that may contain moisture and or chemical contaminants.

Contact Resistance

Resistance in ohms between two conductive objects contacting each other.

Corrosion

Destruction of a metal surface by chemical contamination or oxidation.

Cross Coupling

The effect of coupling a signal from one channel to another.

Cure

The changing of the physical or chemical properties of material by chemical reaction through catalysts, heat or a combination of both.

Cycle Life

A measure of deflection before failure.

dB

Decibels, one tenth of a bel.

Deflection

Difference in height between free and compressed state (gaskets).

Degradation

The change in performance of a material which is undesired but not necessarily a fault.

Dielectric

Having the property of transmitting electric force without conduction; insulating.

Elasticity

The ability of a material to return to its original state.

Elastomer

A polymer which has rubber or elastic like properties.

Electrically Insulating

A material that is unable to conduct electricity due to its high level of electrical resistance.

Electrostatic Charge

An electric charge on an object caused by friction or triboelectric charging.

Elongation

The distance a metal can stretch before breaking relative to original length.

EMC

Electromagnetic Compatibility. The concept of enabling different electronic devices to operate without mutual interference. 

EMI

Electromagnetic Interference.  A disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction.

EMP

Electromagnetic Pulse. High intensity transient electromagnetic fields produced by nuclear explosions.

EPDM

Ethylene propylene diene monomer, an elastomer (rubber).

ESD

Electrostatic Discharge.  The release of static electricity when two objects come into contact with each other.

ESDS

Electrostatic Discharge Sensitive.  Any electronic or electrical component which can be damaged by static charges which build up on people, tools or other non-conductors or semi-conductors.

Fatigue Strength

The stress level over a number of cycles at which failure is unlikely to occur.

Filler

Material added to another material to improve its existing properties or add new ones.

Fluorosilicone

Synthetic rubber used in applications using oils and fuels.

Formability

The ability of a material to be worked cold, for a spring this usually means making bends in the material.

G

Giga (a multiplier 109).

g

Gram.

Galvanic Corrosion

Corrosion occurring between two dissimilar metals.

Grounding

An electrically conductive path between two points.

HAP

Hazardous air pollutant.

Hz

Hertz.  Unit of frequency equivalent to one cycle per second.

I/O

Input/output gaskets used in telecommunications and computer applications. An I/O shield minimises dust that may get into the computer and also creates an electromagnetic shield for the housing.  If several USB devices are connected, an I/O shield will be required to stop interference.

Interference

An energy which interferes with the reception of desired signals.

IP

Ingress protection (dust, water).

IPC

Institute for Printed Circuits, the association connecting electronic industries.

Kg

Kilogram.

M

Mega (a multiplier 10^6).

m

Milli (a multiplier 10^3).

Mar

Resistance to damage by abrasion, scratching.

MEK

Methyl ethyl ketone is an organic compound with the formula CH3C(O)CH2CH3. 

MO

Monel.

Monel

Nickel copper alloy.

Neoprene

Polychloroprene rubber.

Ohm

Unit of electrical resistance.

Ohm/cm

Unit of material volume resistivity.

OPI

Openings per inch (mesh).

PC

Polycarbonate.

PCB

Printed circuit board.

PCI

Peripheral Component Interconnect.

PLA

Poly (lactic acid) or polylactide (PLA) is a biodegradable and bioactive thermoplastic aliphatic polyester derived from renewable resources, such as corn starch.

RDRAM

Rambus dynamic random access memory.

REACH

Registration, Evaluation, Authorisation and Restriction of chemicals (European Union Regulation 2006).

RFI

Radio Frequency Interference. Electromagnetic interference within the frequency range of 3kHz to 300GHz.

RoHS

The Restriction of Hazardous Substances in Electrical and Electronic Equipment Directive (2011/65/EU).

Shielding Effectiveness

Effectiveness of a given material as a radio frequency shield under specific conditions measured in dB.

Silicones

Polymeric elastomer material.

SS

Stainless Steel.

STL File

A file created by a CAD program which is commonly used in 3D printing.

Surface Resistivity

Resistance between two sides of a unit square of its surface.

SVHC

Substances of very high concern.

TC

Tinned copper.

TCS

Tinned copper steel.

Tg

Glass transition temperature.

Thermal Conductivity

The property of a material to conduct heat.

UL

Underwriters Laboratories, the world’s largest not for profit product safety and certification organisation.

Viscosity

Resistance of a fluid to flow under stress.

VOC

Volatile Organic Compound. Organic chemicals that have a high vapour pressure at ordinary room temperature.

Volume Resistivity

Electrical resistance between opposite faces of a centimetre cube of material expressed in ohm centimetre (ohm/cm).