Coplanarity

1. In general, the levelness of the terminals.
2. The maximum distance between the lowest and highest SMT solder tail when the connector rests on a perfectly flat surface. If a part has perfect coplanarity, all of the tails will rest evenly on the flat surface.

Coplanarity is important for surface mount components because they are mounted using a thin film of solder-filled paste. The tighter the coplanarity tolerance, the thinner the solder paste can be. This lowers the cost of manufacturing the finished PCB. This tight lead coplanarity also improves the integrity and hold-down strength of the headers mating to the board.

Copper and Copper Alloys

Copper is the most widely used electrical conductor to wires and cable. Copper and its alloys are used extensively for contacts, fuse clips, terminals, and connectors. On a volume basis, copper has the best conductivity of the common (non-precious) metals. Copper and copper alloys offer excellent corrosion resistance, high thermal conductivity, and ease of fabricating, joining, and forming.

Copper-Covered Steel Wire

A wire having a steel core to which is fused an outer shell of copper.

Copper Foil

Used for shielding in the connector overmolding process.

Cord

A very flexible insulated cable.

Cordwood Module

A module formed by bundling or stacking parts between a pair of end plates, and interconnecting them into circuits by welding or soldering leads together.

Core

1. A material inside a coil that concentrate the magnetic flux. Sometimes referred to as core memory.
2. In fiber optics, the central region of an optical fiber through which light is transmitted. It is defined by the high refractive index region. It is normally in the center of the fiber and is bound by cladding.

Core Memory

Memory that uses small magnetic cores (toroids) as the storage elements. Core memories are nonvolatile, but have destructive readouts.

Corona

The visible glow of an ionized gas surrounding the cathode.

Corrosion

The destruction of the surface of a metal by chemical reaction. Metals vary in their susceptibility to corrosion.

Corrosive Fluxes

Fluxes consisting of inorganic acids and salts; they are generally required where the condition of a surface is well below the ideal for rapid wetting by molten.

Cost Allocation

Distribution of general/shared expenses to the cost centers which derived the benefit of the cost.

Coupled Noise

Transmitted signal data over a line is also transferred over to a nearby victim line appearing as noise on that line. Two kinds of coupled noise exist: Near End Noise (NEN) and Far End noise (FEN).

See also Cross Talk, Near End Noise, Far End Noise.

Coupler

1. A component that transfers energy from one circuit to another.
2. A device that connects three or more fiber ends, dividing one input between two or more outputs or combining two or more inputs into one output.

Coupling

Transfer of light into or out of an optical fiber. (Note that coupling does not require a coupler.)

Coupling Length

In the case of coupled noise, the length or path of wire for the active and victim lines, respectively, essentially running in parallel and close enough physically allowing electromagnetic field interaction and inducing coupled noise (NEN or FEN) in the victim line.

See also Crosstalk, Near End Noise, Far End Noise, Saturation.

Coupling Ring

A device used on cylindrical connectors to lock plug and receptacle together. It may or may not give mechanical advantage to the operator during the mating operation.

Coupling Torque

Force required to rotate a coupling ring or jackscrew when engaging a mating pair of connectors.

Cover

An item specifically designed to cover the mating end of a connector for mechanical and/or environmental protection.

CPA

Connector Position Assurance. An optional lock for Mini-Fit, TPA connectors to ensure the housing cannot be inadvertently disengaged.

CPDR

Cable Products Design Request

CPE

Customer Premises Equipment. Telecommunications equipment and data communications equipment that is located on the customer premises.

CPS

Cycles Per Second. An obsolete label, now replaced by Hertz (Hz).

CPU

Central Processing Unit