Welcome to David Norris Central Data Service

Central Data Service

Online Teaching

(44) (0) 7943055280

Engineering Glossary

Acceleration	a = (vf v0 ) /t, where vf represents the final velocity and v0 represents the initial velocity.
Acceleration of gravity	W= mg, where W represents the force of weight, m represents the mass of the object, and g represents gravity.
Ampere	(amp or A) A unit of electrical current, or flow of electrons, that is equal to a charge of 1 coulomb moving through or across a conductor in 1 second. It is named for Andre M. Ampere, French physicist (1775-1836).
Anodize	Formation of a protective, insulating oxide layer on metal by electronic action.
Back mounted	When a connector is mounted from the inside of a panel or box with its mounting flanges inside the equipment.
Bifurcated contact	A connector contact (usually a flat spring) which is slotted lengthwise to provide additional, independently-operating points of contact.
British thermal unit (BTU)	A unit of heat energy measured as the amount of heat required to raise the temperature of 1 pound of water from 60 to 61 F at a constant pressure of 1 standard atmosphere (the weight of the atmosphere at mean sea level). One BTU is equal to 1054.5 joules in the meter-kilogram-second system of measurements.
Cable assembly	A cable with plugs or connectors on each end.
Cantilevered contact	A spring contact in which the contact force is provided by one or more cantilevered springs. It permits more uniform contact pressure and is used almost exclusively in printed circuit board connectors.
Card edge connector	A connector that mates with printed wiring leads running to the edge of a printed circuit board. Also called Edgeboard connector.
Centrifugal force	F = mv2/gr, where F represents force, m represents the mass of a moving object, v represents its velocity, g represents the acceleration due to gravity (32.2 ftlsec2 ) and r represents the radius of the orbit of the mass.
Conductivity	The ability of a material to conduct electric current. It is expressed in terms of the current per unit of applied voltage. It is the reciprocal of resistivity.
Conductor	A wire or combination of wires not insulated from one another, suitable for carrying electric current.
Configuration	Arrangement of contacts in a multiple-contact connector.
Connector	A device providing electrical connection/disconnections. It consists of a mating plug and receptacle. Various types of connectors include DIP, card edge, two-piece, hermaphroditic, and wire wrapping configurations. Multiple contact connectors with others in one mechanical assembly.
Connector assembly	A mated plug and receptacle.
Connector housing	Insulating material that encapsulated contacts. Once pin and sockets are inserted into the housing, the assembly is called a connector. Connector housings are usually made of plastic, and housing is sometimes called block.
Contact	The conducting part of a connector that acts with another such part to complete or break a circuit; contacts provide a separable through connection in a cable to cable, cable to box, or box to box situation.
Contact alignment	Defines the overall side play which contacts shall have within the insert cavity so as to permit self-alignment of mated contacts. Sometimes referred to as amount of contact float.
Contact engaging & separating force	Force needed to either engage or separate pins and socket contacts when they are in and out of connector inserts. Values are generally established for maximum and minimum forces.
British thermal unit (BTU)	A unit of heat energy measured as the amount of heat required to raise the temperature of 1 pound of water from 60 to 61 F at a constant pressure of 1 standard atmosphere (the weight of the atmosphere at mean sea level). One BTU is equal to 1054.5 joules in the meter-kilogram-second system of measurements.
Cable assembly	A cable with plugs or connectors on each end.
Cantilevered contact	A spring contact in which the contact force is provided by one or more cantilevered springs. It permits more uniform contact pressure and is used almost exclusively in printed circuit board connectors.
Card edge connector	A connector that mates with printed wiring leads running to the edge of a printed circuit board. Also called Edgeboard connector.
Centrifugal force	F = mv2/gr, where F represents force, m represents the mass of a moving object, v represents its velocity, g represents the acceleration due to gravity (32.2 ftlsec2 ) and r represents the radius of the orbit of the mass.
Conductivity	The ability of a material to conduct electric current. It is expressed in terms of the current per unit of applied voltage. It is the reciprocal of resistivity.
Conductor	A wire or combination of wires not insulated from one another, suitable for carrying electric current.
Configuration	Arrangement of contacts in a multiple-contact connector.
Connector	A device providing electrical connection/disconnections. It consists of a mating plug and receptacle. Various types of connectors include DIP, card edge, two-piece, hermaphroditic, and wire wrapping configurations. Multiple contact connectors with others in one mechanical assembly.
Connector assembly	A mated plug and receptacle.
Connector housing	Insulating material that encapsulated contacts. Once pin and sockets are inserted into the housing, the assembly is called a connector. Connector housings are usually made of plastic, and housing is sometimes called block.
Contact	The conducting part of a connector that acts with another such part to complete or break a circuit; contacts provide a separable through connection in a cable to cable, cable to box, or box to box situation.
Contact alignment	Defines the overall side play which contacts shall have within the insert cavity so as to permit self-alignment of mated contacts. Sometimes referred to as amount of contact float.
Contact engaging & separating force	Force needed to either engage or separate pins and socket contacts when they are in and out of connector inserts. Values are generally established for maximum and minimum forces.
Contact plating	Plated-on metal applied to the base contact metal to provide the required contact-resistance and/or wear-resistance.
Contact positions	In most connectors, the maximum number of contacts that can be actively engaged. In edge connectors, the number of contact positions along the length of the connector as opposed to the total number of contact
Contact resistance	Maximum permitted electrical resistance of pin and socket contacts when assembled in a connector under typical service use.
Contact retention	The minimum axial load in either direction which a contact must withstand while remaining firmly fixed in its normal position within the connector insert or housing.
Contact size	Defines the largest size of wire which can be used with the specific contact. By specification dimensioning, it also defines the diameter of the engagement end of the pin.
Coulomb	(coul or C) The amount of electric charge that crosses a surface in 1 second when a steady current of 1 ampere is flowing across the surface. It is also equivalent to 6.3 x 101e electron charges. Named for Charles A. Coulomb, French physicist (1736-1806).
Coulomb’s law	F= kX (Q4Qb/d2) where F represents the electrostatic force, k represents a constant of proportionality,Q4 and Qb represent quantities of electrostatic charge, and d represents the distance between the charges.
Crimp contact	A contact whose back portion is a hollow cylinder to allow it to accept a wire. After a bared wire is inserted, a swedging tool is applied to crimp the contact metal firmly against the wire. A crimp contact often is referred to as a solderless contact.
Crimp termination	Connector in which a metal sleeve is secured to a conductor by mechanically crimping the sleeve with pliers, presses, or automated crimping machines. Splices, terminals and multi-contact connectors are typical terminating devices attached by crimping. Suitable for all wire types.
Crimping tool	Mechanism used for crimping.
Current	A movement of electrons, positive ions, negative ions, or holes; the rate of transfer of electricity from one point to another. Current is usually measured in amperes.
Current rating	Maximum current which a device is designed to conduct for a specified time at a specified operating temperature.
Detent	A dimple, depression, or hole in a male tab which acts to engage a raised portion on the connector.
Dielectric	A solid, liquid, or gaseous material that can sustain an electric field and act as an insulator.
Dielectric withstanding voltage	The maximum electric field that can be sustained by a dielectric before breakdown occurs.
Din connector	Refers to DIN 41612, the standard developed by the German Institute for Standardization, and the Association of German Electrical Engineers. It covers a variety of connector styles and is based on a family of 64 and 96 position, 2-piece PCB connectors having contact tails for soldering on 0.100 or 0.200″ centers.
Dip solder terminal	The terminals on a connector which are inserted into holes in the PC board and then soldered in place.
Electrical power	P =IV; where P represents power, I represents electrical current, and V represents electrical potential.
Energy-matter relationship	E = mc2 where E represents energy, m represents mass, and c represents the velocity of light.
EMI	Electromagnetic interference.
Edgeboard connector	A connector that mates with printed wiring leads running to the edge of printed circuit board. Also called card edge connector.
Embossment	Located on the base of a female connector, its function is to keep the sides of the male from interference due to the radii on the bottom of the sides of the connector. When possible, it provides a “lead in” for the male tab.
Environmentally sealed	A connector provided with gaskets, seals, potting or other devices to keep out moisture, dirt, air or dust which might reduce its performance.
Extraction tool	A tool used for removing a contact from a connector. A device used for removing taper pins from taper pin receptacles.
Female Connector	Portion of a quick-connect wiring termination which receives the male tab.
Flash plating	The application of extremely thin deposits of a plating mater al for environmental protection or as a base for a subsequent layer of plating material.
Flat cable connector	Connector designed specifically to terminate flat cable. May be designed for flat conductor, flat cable, or round conductor, flat cable.
Gold	The standard coating for edge connectors over a base of either nickel or copper. The common plating consists of 10 micro inches of gold over either 20 inches of nickel, or 50 micro inches of copper.
Gravity inverse square law	F = g x Mm/r2 where F represents force, g represents the pull of gravity, M and m represent the masses of two objects, and r represents the distance between the masses.
Hood	An enclosure, attached to the back of a connector, to contain and protect wires and cable attached to the terminals of a connector. A cable clamp is usually an integral part of a hood.
Housing	Connector less insert, but with insert-retaining and positioning hardware required by standard construction.
Insertion force	The effort usually measured in ounces, required to engage mating components.
Insulation Ear	Part of a terminal which is designed to be crimped on the insulated portion of a wire. It acts as a strain relief for the wire ear and prevents damage to the wire from flexing.
Insertion tool	A small hand-held tool used to insert contacts into a connector.
Insulation	A material which offers high electric resistance making it suitable for covering components, terminals, and wires to prevent the possible future contact of adjacent conductors resulting in a short circuit.
Insulator	A material of such low electrical conductivity that the flow of current through it can usually be neglected.
Joule (J)	A unit of energy or work equal to the force of 1 newton magnitude when the point at which the force is applied is displaced 1 meter in the direction of the force. Named for James P. Joule, English physicist (1818-1889)
Kinetic energy	KE =1/2 mv2, where KE represents kinetic energy, m represents the mass of a moving object, and v represents the velocity.
Light inverse square law	I1/I2=(d2/d1)2, where I1 represents the light intensity at distance d1 from the source and I2represents the intensity of light at distanced d2 from the Source.
Male Tab	Portion of a quick-connect wiring termination which receives the female connector.
Mass termination	Method of termination in which terminals that pierce flat cable insulation without stripping to cold flow mate with conductors and form a gas-tight metal-to-metal joint.
Mass and weight relationship	m1/m2 = W1/W2, where m1 and m2 represent two masses and W1 and W2 represent the sizes of their respective weights.
Momentum	p = mv, were p represents momentum, m represents the mass of the object, and v represents velocity.
Newton (N)	A unit of force equal to the force that will cause an acceleration of 1 meter per second squared to a mass of 1 kilo gram. Named for Sir Isaac Newton, English mathematician (1642-1727).
Newton’s second law	F= ma, where F represents force, m represents mass of the object, and a represents the accelerated movement.
Nib	Raised portion on the connector which acts to engage a detent.
Ohm (Ω)	A unit of electrical resistance through which a current of 1 ampere will flow when there is a potential difference of 1 volt across it. Named for George S. Ohm, German physicist (1787-1854).
Ohm’s law	R= V/I, where R represents electrical resistance, V represents electrical potential, and I represents electrical current, potential energy
Operating temperature	The maximum internal temperature resistant capabilities of a connector in continuous service.
Pin contact	A male type contact, usually designed to mate with a socket or female contact. It is normally connected to the “dead” side of a circuit.
Plating	The overlaying of thin coating of metal on metallic components to improve conductivity, provide for easy soldering, or prevent rusting or corrosion.
Plug connector	An electrical connector intended to be attached to the free end of a conductor, wire, or cable or bundle, which couples or mates to a receptacle connector.
Power	P= work/t, where P represents power and t represents the time required to perform the indicated work.
Quick-Connect Wiring Termination	Electrical connection consisting of a male tab and female connector. It can be readily engaged and disengaged without the use of tools.
Rails	Spring portion of a female connector which provide the “normal force” required to assure a good electrical connection with the male tab. They must be able to be engaged and disengaged repeatedly while still maintaining their integrity.
Rack and Panel	A rack and panel connector is one which connects the back end of the cabinet (rack) with the drawer containing the equipment when it is fully inserted. The drawer permits convenient removal of portions of the equipment for repair and examination. Special design and rugged construction of the connector allows for variations in rack and panel alignment.
Rated temperature	The maximum temperature at which an electric component can operate for extended periods without loss of its basic properties.
Rated voltage	The maximum voltage at which an electric component can operate for extended periods without undue degradation or safety hazard.
Removable contact	A contact that can be mechanically joined to or removed from an insert. Usually, specials tools are required to lock the contact in place or remove it for replacement.
Removal tool	(1) A device used to remove removable contacts from a connector. (2) A device used to remove taper pins from taper pin receptacles.
Screw-machine-contact	A contact made by screw-machine operations.
Selective plating	The application of plating material to a limited portion of a connector contact, especially those areas susceptible to wear.
Serrations or Ribs	Depressions on the inside of the wire ear which are designed to increase the mechanical holding force between the wire and wire ear. They improve the electrical performance of the crimp by mechanically disrupting oxides during the crimping process. The only distinction between the two is that ribs are visible on the external surface of the wire ear and typically used in thinner materials.
Shell	Outside case into which the insert and contacts are assembled. Shells of mating connectors usually also provide proper alignment and protection at projecting contacts.
Shielding	The metal sleeving surrounding one or more of the conductors in a wire circuit to prevent interference, interaction or current leakage.
Socket connector	A connector containing socket contacts into which a plug connector having male connections is inserted.
Solder cup	A tubular end of a terminal in which a conductor is inserted prior to being soldered. It is also the hollow cylinder at the rear of a solder contact where a wire is inserted and soldered in place.
Stamped contacts	Contacts made by stamping and bending sheet metal rather than by machining of metal stock.
Termination	The load connected to the output end of a circuit, device or transmission line.
Thermoplastic	A type of plastic which can be remelted a number of times without any important change in properties.
Velocity	v= d/t, where d represents the distance traveled in time t.
Volt (V)	A unit of electromotive force equal to the potential difference between two points for which 1 coulomb of electricity will do 1 joule of work in going from one point to the other. Named for Count Alesandro Volta (1745-1827).
Watt (W)	A unit of electrical power equal to 1 joule per second. It is also measured as the product of the amperes multiplied by the volts. Named for James Watt, Scottish inventor (1736-1819).
Wave equation	V=fw, where V represents the velocity of the wave, f represents its frequency, and w represents the wavelength.
Weight	Wt = mg, where Wt represents the weight of an object, m represents its mass, and g represents the pull of gravity.
Wire Ear	Part of a terminal which is designed to be crimped on the stripped portion of a stranded or solid wire.
Wire wrapped connection	A solderless connection made by wrapping bare wire around a square or rectangular terminal with a power or hand tool. Also called Solderless wrapped connection; or Wrap post connection.
Work	W= fd, where W represents work, f represents the applied force, and d represents the distance over which it is applied.
Wrap post	See Wire wrapped connection.

Home

Downloads (PDF ETC)