Glossary & Terminology - Electronic Connectors
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- Acrylonitrile Butadiene Styrene (ABS) is an amorphous thermoplastic tri-polymer that finds exceptional use in the connector industry because of low cost, dimensional stability, high impact resistance, excellent mechanical properties, good working temperature range, and high surface hardness.
- Abrasion Resistance
- Abrasion Resistance is the degree of resistance of a material to abrasion or surface wear
- Alternating Current. An electrical current that reverses its direction of flow at regular intervals (ac, 60 hertz [cps] means reversing direction of flow each half cycle or 120 times per second).
- Acetal is a crystalline thermoplastic used in the fabrication of connectors. Acetals possess properties similar to metal and offer good resistance to organic solvents. Owing to its flammable chemical composition, no flame resistant grade of Acetal exists.
- Acetal Resin
- Acetal Resin is a rigid Thermoplastic Resin with mechanical properties similar to Zinc or Aluminium. Acetal resin can be moulded or extruded to provide high tensile and flex strengths, resilience and solvent resistance. Good electrical properties survive humid conditions.
- Access Holes
- Access Holes is a series of holes that share a common axis, often used to link layers of printed circuit boards
- Actuator is a sliding, wedge-like device that pushes a Flexible Printed Circuit (FPC) or a Flat Flexible Cable (FFC) contact against a connector contact. The wedge action generates high Contact Normal Forces and FPC/FFC Retention Forces.
- Alkyd Resin
- Alkyd Resin is a type of Resin made from a Polyhydroxy alcohol combined chemically with the acids of various oils. They are particularly adapted for use where hardness and high gloss are required. They are commonly used as thermosetting moulding compounds in electronic components.
- Alloy is a combination of a metal with another element such as another metal or even a non metal.
- Allyl Plastics
- Allyl Plastics are plastics based on resins made by addition polymerization of monomers containing Allyl groups, such as diallyl phthalate. Often compression molded, offering good high temperature performance and chemical resistance.
- Alternating Current, AC
- Alternating Current is an electrical current that reverses its direction of flow at regular intervals (AC 60 Hertz [Hertz is number of cycles per second] means reversing its direction of flow each half cycle or 120 times per second).
- Aluminum, Al
- Aluminum is element no. 13 of the periodic system; Atomic weight 26.97; silvery white metal of valence 3; melting point 1220 (degrees F); boiling point approximately 4118 (degrees F); ductile and malleable; stable against normal atmospheric corrosion, but attacked by both acids and alkalis. Aluminum is used extensively in articles requiring lightness, corrosion resistance, electrical conductivity, etc. Its principal functions as an alloy in steel making; (1) deoxidizes efficiently; (2) restricts grain growth (by forming dispersed oxides or nitrides); (3) alloying element in nitriding steel.
- Ambient Temperature
- The temperature of the air, or surrounding earth, is used as a test environment in product specifications.
- Ampere, A
- Ampere is the standard unit of the current passing, designated as the amount of current that occurs when one Volt of Electromagnetic Force (EMF) is applied across one Ohm of Resistance. An ampere of current is produced by one Coulomb of charge passing a point in one second through a conductive material cross-section.
- Analogue describes the variableness of a measurable quantity that takes a continuous set of values.
- ANSI is the abbreviation of American National Standards Institute.
- An Arc is a spark or flash caused when a high voltage ionizes a gas or vapour.
- Array is a collection of data items; all of the same type, in which each item's position is uniquely designated by an integer.
- Au / Sn
- Au / Sn are a solder alloy of Gold & Tin, usually in 80/20 ratio used for sealing gold plated packages.
- AWG is the abbreviation of American Wire Gauge, which is a system of conventional designations of standard wire diameters. For example, "10 Gauge" denotes wire of 0.135-inch diameter. In the AWG system, higher numbers designate smaller diameters and lower numbers designate larger diameters.
- Back mounted
- A connector attached to the inside of a panel (or box) with its mounting flanges inside the equipment.
- A power-supply feature that prevents discharging of the output capacitor when the power supply starts up.
- Bill of Material (BOM)
- Bill of Material, or abbreviated as BOM, is a list of all electrical, electronic, mechanical parts or components, or other supporting materials that are required to manufacture the complete end product. A simple BOM lists out the manufacturing part numbers and the quantity needed of each component. Depends of the complexity of the end product, it will be consisted of multiple levels of sub-assemblies and thus the BOM is hierarchical and may contain many modular BOM for each sub-assembly. To describe completely about the parts and components that will be used in the manufacturing processes, sometimes the BOM will also include a whole range of component descriptors, e.g. specifications, CAD drawings, schematic diagrams, mechanical and electrical characteristics, etc. In a nutshell, BOM serves as a mean to track product changes, costing, inventory control, engineering management, maintaining an accurate list of components needed to manufacture the product. In particular, when manufacturing outsourcing is popular, sharing the BOM from OEM to an EMS provider, via web-based Product Data Management (PDM) or Enterprise Resources Management (ERP) systems is very essential to seamless integration of supply chain.
- Where a voltage is output in a higher voltage.
- Bottom Mount
- When card entry is normal, i.e. contacts of the card are facing downward, if the card socket is mounted on the “Bottom” of the PCB board, it is said to be Bottom Mounted. In other words, when card entry is reversed, i.e. contacts of the card are facing upward, if the card socket is mounted on the top of the PCB board, it is said to Bottom Mounted. It is sometimes called Reverse Mount, which refers to, if a Bottom Mount card socket is mounted on top of a PCB, the card entry needs to be reversed. In terms of structure, in a Bottom Mount card socket, the contact terminals of the card socket are of the opposite horizontal plane as of the SMT pins. See the following diagram for details:
- Bulk Resistance
- Contact resistance that is caused by the length, material of a contacts cross section.
- Type of connector designed for insertion into a panel cutout on the component side.
- Electrical devices on a circuit board use a bus as an information highway, in which the bus can send data from one device to another.
- Cable Assembly
- A cable that is ready for installation in specific applications & usually terminated with connectors.
- An ethernet cable standard used in unison with modular jacks to connect across printed circuit boards (for example within a local area connection).
- A capacitor is a passive electrical component that can store energy in the electric field between a pair of conductor plates.
- A configuration of electrically or electromagnetically connected components or devices
- Contact Resistance
- The contribution to the total resistance of a material which comes from the electrical leads & connections.
- Closed Circuit
- An electrical circuit through which current can flow, such as when a power switch is moved to the "on" position. Closed circuit is the opposite of an "open" circuit.
- Contact Type (SIM)
- An economical connector for use in applications where the SIM card is integrated into the end equipment, the card rests on the connector contacts.
- The number of pin contacts on a board to board connector.
- Contract Electronics Manufacturer (CEM)
- Contract Electronics Manufacturer (CEM) refers to a company that manufactures and assembles products for another hiring company. That hiring company is typically an Original Equipment Manufacturer (OEM) which owns the brand, design and the intellectual property of the product, but outsources the manufacturing of the product to a CEM. Because CEMs are typically sub-contractors of many other OEMs of the same kind, they gained advantages and expertise in large capacity manufacturing, raw material sourcing, industrial designs, quality controls, and thus become even more competitive in those areas than a single OEM. On top of that, CEM provides value-added services to an OEM, such as order fulfilment, distribution, engineering service, etc, making an OEM can operate without a real factory. It is also very common for OEMs to outsource their older, more stable product lines to their CEMs, and focus themselves on some higher growth, higher profit margin products.
- The state of being whole, unbroken.
- Crimp contact
- An electrical terminal or contact having a wire barrel that has been formed or machined into a hollow cylinder or left to remain as an open "U." After a wire has been inserted, the barrel is wedged into a controlled form that will continue to exert pressure on the wire. A crimp contact is often referred to as a solderless contact.
- Dielectric withstanding voltage
- The maximum potential gradient that a dielectric material can withstand without failure.
- Differential (Signalling)
- Two wires are used to counteract each other, they act as the inverse of each other (i.e. one positive and one negative), and this is beneficial as it allows reduction on the impact of electrical interference.
- Decabromodiphenyl ether is a flame retardant, made from organic compounds containing bromine.
- Dielectric Withstanding Voltage Test
- Both EIA-364-20 & MIL-STD 1334A Method 3001 describes the procedures of testing the Dielectric Withstanding Voltage of a connector. Purpose of the test is to prove a connector which can operate safely at its rated voltage, and can also withstand momentarily over potentials due to unstable switching. Therefore, during testing, a high voltage AC source (voltage at least 75% of the break-down voltage of the connector) is applied across adjacent contact terminals of the connector for around 1 minute. Then measure the leakage current (must be less than 5mA) and see if there is any spark or damage physically. If the connector can withstand the voltage, the rated voltage of the connector is usually specified as one third of the Dielectric Withstanding Voltage. It is also specified at the sea level. For higher altitude at lower Barometric pressure, a lower Dielectric Withstanding Voltage is required.
- A device that passes current in only one direction using two terminals, normally a semiconductor.
- Durability Test
- Both EIA-364-09 and MIL-STD-1334A Method 2016 describes the procedures of testing Durability of a connector. Purpose of the test is to determine the effects on the connector or on the contacts after subjecting it to a certain number of mating and unmating cycles (e.g. 10,000 cycles for Micro-USB connectors) at a specified rate, simulating the expected life of such connectors. At the completion of the specified number of mating and unmating cycles, the connector test specimen will be visually examined to see if there is any physical damage, wearing, displacement, bending, etc, or measuring some critical performance parameters, e.g. contact resistance, to see if the connector is maintaining its performance within the specification after the test.
- Electrical circuits may have a direct physical connection to the Earth, a connection to ground helps limit the voltage, protecting circuit insulation from damage due to excessive voltage as well as limiting the build up of static electricity.
- Technology involving the manipulation of voltages & electric currents through the use of various devices.
- Electronic Industries Alliance, EIA
- A standards organization for electrical and mechanical testing procedures, managed by the Electronic Components Association.
- Electronic Manufacturing Service
- Electronic Manufacturing Service providers are basically CEMs that provides substantial vertical value-added services to OEMs. Apart from offering manufacturing services, EMS providers offer design services, testing services, supply chain management, global distribution, logistics, customers support, warranty, and repairing services to their OEMs customers. Foxconn, Flextronics, Solectron, Sanmina-SCI, Jabil, Celestica are all EMS companies.
- Entry Type
- Defines the point in which a component enters a Printed Circuit Board; vertical, horizontal, right angle & straight types are most common in board to board connectors.
- Flat Flex Cable: a cable that is highly durable & designed for moving applications such as scanners.
- Flexible Printed Circuitry is a type of printed circuit board. The flexible printed circuit board has properties of flexibility, lightness, soft, thinness, smallness & ductility.
- Flat Flexible Cable (FFC) Connector
- FFC, Flat Flex Cable, is a set of parallel metal conducting strips laminated between two dielectric films that form a flat and flexible tape-like cable. FFC is a miniature of Ribbon Cable (round & flat) that are often used in personal computer connecting disk drives to motherboard. Flat Flex Cable is terminated in a FFC connector (socket) of Low Insertion Force (LIF) or ZIF (Zero Insertion Force), which depends on the Pin counts and Pin Pitch. For high Pin density applications, ZIF socket is used more often. FFC connectors could have various pitches (from 0.2mm to 2.54mm), orientations (straight or right-angle), contact types (top or bottom contacts) and mounting types (surface mount or through-hole).
- The patterns on the printed circuit board to which the leads on a surface mount component are terminated or soldered.
- Friction Type (SIM)
- An economical connector for use in applications where the SIM card is integrated into the end equipment, the card rests on the connector contacts.
- Please refer to Header (male) & Socket (female).
- Please refer to earth.
- Global System for Mobile Communications, GSM
- A land, mobile, pan-European, digital, cellular radio-communications system.
- Header (male)
- A connector with extruding pins of a two piece assembly which mates with a socket.
- Heat Sink
- A conductor that is used to reduce the amount of heat affecting a component, generally made from aluminium.
- Housing is made of insulative material (mostly plastic) used to provide a touch-safe enclosure for components.
- Hinged Type
- Hinged Type is a type of card connector mechanism commonly used in SIM card and Memory card connectors. It features a cover and an insulating housing with landed contact terminals and chamfered corners in assuring right direction of card insertion. The cover and the insulating housing are connected with each other through a hinge. By sliding out and pulling up the cover, users can insert or place the card directly on the contact terminals, and thus make the connection. Then users can push down and slide in the cover to secure the connection. Hinged type SIM and Memory card connectors are commonly found in mobile phones.
- Insertion Force
- Required force to insert a male header into a female socket.
- Insulators (dielectric)
- A material that resists the flow of electric current, normally a plastic mould is used in electrical components.
- ISO 9001
- A standard that provides a number of requirements which an organization needs to fulfil if it is to achieve customer satisfaction through consistent products & services which meet customer expectations.
- Integrated heat spreader
- The surface used to make contact between a heatsink and component.
- IR Reflow
- A soldering process that uses infrared light, this light is used as a method of heat transfer known as radiation.
- A jumper is a short length of conductor used to close a break or bypass part of an electrical circuit (also known as a shunt).
- Please refer to lock tight.
- LCP, Liquid Crystal Polymer
- LCP is a class of Polyester Polymer, which has excellent heat resistance of melting point up to 370 oC, exceptional chemical resistance, inherent flame retardancy and strong mechanical strength. One of its advantages is its high crystallinity, and is capable to form regions of highly ordered structure during moulding or at its molten state. However, it is more expensive than other connector housing materials such as PBT.
- Lock Tight
- Board to board connector feature, in which a pin is bent out to create a locking mechanism after insertion through the PCB (also known as 'kinked').
- A type of solder that is lead free, due to toxicity levels recorded by a life-cycle assessment by the Environmental Protection Agency on lead solder, industry standard directives concentrated its efforts to reduce impact on the environment.
- Mega-Ohm, MΩ
- A unit of electrical resistance equal to one million ohms.
- Milli-Ohm, mΩ
- A unit of electrical resistance equal to one thousandth of an ohm.
- Memory Card
- A memory card connector includes an insulating housing defining conductive terminal grooves and two locating grooves at a sidewall there of. A shelter shell coupled with the insulating housing to form a card cavity has a top section and two side sections. A front surface of the top section extends frontward and then extends downward to form two anti-mismating portions adjacent to the two side sections. The two anti-mismating portions have different width and vertical length. Conductive terminals are fixed in the conductive terminal grooves and soldered to a printed circuit board (PCB) for electrically engaging with corresponding contacts of a memory card inserted into the card cavity. A pair of switch terminals mounted in the locating grooves and soldered to the printed circuit board. One switch terminal is pressed outward by the memory card fully inserted into the card cavity, which causes the two switch terminals to contact with each other for grounding.
- Multi Media Card (MMC) is a 7-pin miniature flash memory data storage system. It was released by Infineon / Siemens and SanDisk in 1997. Comparing to its earlier rival, Compact Flash (CF), which was released in 1994 by SanDisk, MMC is based on Toshiba’s NAND flash memory architecture, rather than Intel’s NOR flash memory architecture, which enables MMC to have a higher data density, and thus smaller card size & weight (24x32x1.4mm, weights about 2g) than the CF (43×36×3.3mm, weights about 10g). Because MMC was designed for lower power consumption, and wide supply of voltage range, it favours many battery-operated and mobile applications, such as digital camera, mobile phones, MP3 players, PDA, etc. It is later largely superseded by the introduction of the 9-pin Secure Digital (SD) memory card (card size: 24x32x2.1mm) in 2000. As a result, a typical SD card connector will also accommodate a MMC memory card, but not vice-versa.
- Micro SD
- Micro SD is the smallest Memory Card of SD (Secure Digital) Series and also the smallest Memory Card available on the market commercially. It is originally introduced by San Disk in 2004 called T-Flash or Trans-Flash, and was later adopted by the SDA (SD Card Association), with another name called Micro SD. Micro SD Card are backward compatible to SD enabled device by using appropriate adapter. It features a dimension of only 11mm (Width) by 15mm (Height) by 1mm (Thickness), which is much smaller comparing to the SD Card and makes it more suitable for smaller, next-generation portable devices.
- Micro USB
- Micro USB Connectors include both B and AB. Its reduced size makes it more suitable for smaller portable USB devices since they are 60% smaller than a Mini sub.
- Mini USB
- Mini USB Connectors include both Mini-A, Mini-AB (they were already deprecated by USB-IF in May 2007 and to be replaced by Micro-A, and Micro-AB Connectors), and Mini-B connectors (it was released by USB-IF as the first ECN, Engineering Change Note, of the USB2.0 Specification in October 2000). Initial purpose of releasing Mini-B USB connectors (plugs & receptacles) is to replace the “Standard B” USB connectors, because these device-side connectors seems to be too large for the newer generation of USB devices such as Smart-phones, PDA, Digital Cameras, MP3, etc. "Standard B" USB connector is around 8mm (Height) by 8mm (Width), while Mini B USB connector is only around 4mm (Height) by 7mm (Width). Its reduced size makes it more suitable for smaller portable USB devices.
- Minimum Order Quantity – Generally a cost beneficial stated minimum for mass production of a component.
- Mount Type
- Methods for mounting components on a printed circuit board (PCB), including surface mount & through-hole.
- Mylar Packaging
- A type of packaging, a form of polyester film, that has qualities such as excellent dielectric strength, moisture resistance & physical durability.
- Number of Rows
- Please refer to rows.
- Nylon 6T
- Nylon 6T, also known as Polyamide 6T, PA 6T, or Poly-Hexa-Methyleneterephthalamide, which has excellent heat resistance of high melting point at around 370 oC, which is more suitable for High Temperature processes like Reflow and Wave Soldering than its lower cost competitor PBT.
- Over Current - A current in a circuit exceeds the rated amperage capacity of that circuit or of the connected equipment on that circuit.
- A unit of electrical resistance equal to that of a conductor in which a current of one ampere is produced by a potential of one volt across. Please also refer to milli and mega ohm.
- Please refer to straight (vertical) and right angle (horizontal)
- Original Equipment Manufacturer
- Original Equipment Manufacturer refers to a company that owns the brand and also designs of the products. Traditionally, OEMs design the product; purchase the components from their suppliers; operating their own production lines; handle sales, customers support and service on their own. However, many of these functions, in particular, manufacturing & assembly, are outsourced to CEMs or EMS providers.
- Original Design Manufacturer
- Unlike OEMs which own the brand, an Original Design Manufacturer (ODM) designs and probably manufactures the products themselves, but sell the product under an OEM brand. ODM only owns the design of the product and its intellectual property, but not selling the product in their brand.
- PBT or Poly-Butylene Terephthalate is a type of Polyester, a kind of cost-effective thermoplastic with excellent insulation resistance, good mechanical strength, dimensional stability, chemical solvent resistance and heat resistance up to 150oC (up to 200 oC with glass filled), that are commonly used as insulation housing of a connector. However, Lead-free wave soldering or reflow soldering requires insulators of higher temperature resistance, leading PBT less popular than Nylon 6T or LCP for High Temperature process, although it has a cost advantage over them.
- Printed Circuit Boards - is a non-conductive material with conductive lines printed or etched. Electronic components are mounted on the board & the traces connect the components together to form a working circuit or assembly.
- Pick and Place Machine
- Pick & Place Machine, or called SMT component placement system, is a programmable machine with robotic arms that pick up components from an automatic feeder, then moves to a specified location on a PCB and place the components onto that location.
- Pitch (pin)
- The length between two pins on an electrical component, such as a board to board connector.
- Used on components, to coat pins for protective purposes, tin is used frequently in the electronics industry for its ability to protect base metal from oxidation, preserving there solderability.
- A feature of a product which enables mating of a receptacle in only one orientation/alignment.
- Post is an option provided on components to secure themselves to PCB's.
- Push push a type of connector device used in conjunction with SIM and memory cards, the user pushes the SIM/memory card into the device until it stops springing back, this locks it in place. To release it the SIM / memory card is pushed once more removing the lock mechanism, so the card can be removed.
- REACH is the new regulation on Registration, Evaluation, Authorisation and Restriction of Chemicals and their safe use (EC 1907/006). Major objective of REACH is to set up a Registration, Evaluation, Authorisation, and Restriction system to identify production and excessive use of SVHC (Substances of Very High Concern, currently the candidate list is consisted of 15 substances) chemicals in articles that will have potential negative impacts on human health and the environment. The REACH Regulation had entered into force in 1 June 2007. Manufacturers and importers of SVHC substances of over 1 tonnes per year into EU are required to gather information on the properties of their chemical substances, and to register the information in a central database run by the European Chemical Agency. The Agency will manage the public database (consumers can find hazardous substances information there) and coordinate evaluation of suspicious chemicals. Unlike RoHS that only applies to electrical and electronic goods, REACH applies to all kinds of substances, preparation and articles that are produced or will be imported into EU.
- Reflow Solderable:
- Describes a product that can withstand the elevated temperatures associated with reflow of 260°C+ & the extended dwell times required during processing. Please also see http://en.wikipedia.org/wiki/Reflow_soldering
- A resistor is an electrical component that limits or regulates the flow of electrical current in an electronic circuit.
- Retainer Type
- SIM card holding mechanism, the SIM card slides onto the contacts & is held in place either under a fixed retaining top cover or between retaining slots. A chamfered corner prevents the SIM card being wrongly inserted.
- Right angle (connector)
- A connector which is has a right angle bend.
- RoHS certified
- The restriction of the use of certain hazardous substances in electrical and electronic equipment.
- Horizontal pin arrays on a board to board connector.
- Secure Digital memory card - Used primarily in phones, PDA’s & other digital devices to store information, which can be accessed at high data transfer rates.
- A substance that can act as an electrical conductor or insulator i.e. silicon.
- A Subscriber Identity Module is a way of securely storing the service-subscriber key (IMSI) used to identify a mobile phone subscriber.
- Socket (female)
- A socket is half of a two piece multiple contact connector and is usually the half that is fixed. It contains socket contacts into which a male header (plug) is inserted.
- Stacking Height
- The distance between the inside faces of two parallel mounted PCBs.
- Straight (connector)
- A connector which is perpendicular.
- Surface mount technology (SMT) / Surface mount design (SMD)
- A method for mounting components on a printed circuit board (PCB) in which a component is placed in parallel with the board & soldered in place. Please also see http://en.wikipedia.org/wiki/Surface-mount_technology
- Switch is a device that makes, breaks, or changes the state of a connection. It could be a mechanical, electrical, electro-mechanical, thermal or optical switch. In terms of circuit topology, number of poles of a switch is the number of the contact positions connecting to the circuit, while number of throws is the number of possible switching positions. The simplest type of switch is a SPST, Single Pole, Single Throw switch, which switches between "on" (make connection) and "off" (break connection) states. Switches are commonly found in Push-type SIM and Memory card connectors, e.g. there are Write Protect Detection Switch and Card Detect Switch inside a SD Memory card connector. During the insertion of the media card, switches are activated and switched, and an electrical signal is generated and recognized as "READ CARD".
- Tape on Reel Packaging
- A form of component packaging used in conjunction with highly automated equipment to perform packaging functions.
- Terminals transmit the current/signal between PCB's connected by board to board, made from a conductive material (mostly copper alloy), & plated to improve conductivity & antirust.
- Through hole / Thru hole Technology
- A method for mounting components on a printed circuit board (PCB) in which pins on the component are inserted into holes in the board & soldered in place.
- Please refer to Micro SD
- Top Mount
- When card entry is normal, i.e. contacts of the card are facing downward, if the card socket is mounted on the “Top” of the PCB board, it is said to be Top Mounted. In other words, when card entry is reversed, i.e. contacts of the card are facing upward, if the card socket is mounted on the bottom of the PCB board, it is said to be Top Mounted. It is sometimes called Standard Mount, because it is the most common standard mounting type nowadays. In terms of structure, in a Top Mount card socket, the contact terminals of the card socket are of the same horizontal plane as of the SMT pins, See the following diagram for details:
- Universal Serial Bus (USB): A standard port that enables you to connect external devices (such as digital cameras, scanners, keyboards, & mice) to computers. USB ports are available as USB-A and USB-B (aka A type and B type) and are available as Mini USB and Micro USB. USB power requirements define a supply and output voltage of 5V, with output currents rated at 0.5A for self-powered equipment and 0.1A output for bus-powered equipment.
- The Standard-A type of USB connectors takes on the appearance of flattened rectangles that plugs into downstream-port sockets on the USB host or a hub. This kind of connector is most frequently seen on cables that are permanently attached to a device, such as one on a cable that connects a keyboard or mouse to the computer.
- Standard-B connectors—which have a square shape with bevelled exterior corners—typically plug into upstream sockets on devices that use a removable cable, e.g. between a hub and a printer. This two-connector scheme prevents a user from accidentally creating a loop.
- USB-IF is an abbreviation of USB Implementers Forum, which is a non-profit industry organization made up of Original Equipment Manufacturers (OEMs), Components, Cable & Connectors Manufacturers, and Software / Firmware Developers, aiming at advancing the USB technology and implementations.
- Underwriters Laboratories is a non-profit privately owned & operated product safety testing & certification organization, developing standards and test procedures for material, products, components, tools, assemblies & equipment.
- UL 94 is the flaming rating of the flammability of a plastic. It is a measure of flame resistance, i.e. how quick an ignited flame on a burned specimen will come to be extinguished naturally. Depends on the orientation (horizontal and vertical) of the specimen during the flaming test, its material (plastic or foam), its thickness (e.g. thin material), and its flame retardancy, materials are rated and classified into 12 classes. UL94-V0 specifies if a vertical positioned specimen was burned for 10 seconds vertically at its bottom, it must stop burning within 10 seconds after the flame was removed, and it will not drip off particles that will ignite the cotton placed below it. 2 sets of 5 specimens are tested. UL94-V0 is the highest rating in the UL94 flammability test, e.g. UL94-V2 requires the vertically burned specimen stops burning within 30 seconds, while UL94-V0 requires it stops burning within 10 seconds) This standard is released by UL Laboratories, and is similar to IEC 60695-11-10.
- Vernier Scale
- Is used to measure a distance or angle, being more precise than directly reading a straight or circular measurement scale is used by machinists in the manufacturing industry.
- Voltage, V
- Electrical force which causes current to flow through a conductor.
- Wave Solderable
- Describes a product that is compatible with wave solder temperatures of 260°C+ with maximum exposure of the termination pins to the solder wave for 6 seconds.
- Wing Block
- Wing Block describes the metallic cover on retainer SIM connectors. Also known as 'Bridge Cover'.
- Write Protect, WP
- Any method that prevents data from being over-written.
- Zero Insertion Force (ZIF), describes a kind of female socket, when a male component is being inserted, only “zero” or very negligible force is needed for insertion and extraction. It is firstly used in IC Socket, when the Process Pin Count is high, the total insertion or extraction force will be high enough to break the soldered connections or even the PCB itself. ZIF Socket was thus invented, with a lever, or a notch, or a slider, or a latch, when it is opened, the sprung contacts inside the socket were pushing apart, and inserting the male component, e.g. a Flat Flex Cable, therefore requires almost no pressure at all. When the latch is closed, it causes the contacts to close and grip the contacts of the male component, and thus secure the connection. Compared to the simpler LIF Socket, Low Insertion Force Socket, ZIF Socket takes up more space owing to the additional slider or the drawbar, and thus cost more. It is often used in high pin density applications, where non-zero insertion forces will accumulate to become a damaging effect. Therefore, ZIF socket is more durable and can withstand larger number of mating cycles.