NC drill Numeric Control drill machine. A machine used to drill the holes in a printed board at exact locations, which are specified in a data file

NC drill file A text file which tells an NC drill where to drill its holes.

NC (Numeric Control) equipment Any machine whose activity is commanded by instructions that are input to a programmable controller.

NC fabrication equipment Numerically controlled machine tools such as routers and drilling machines.

neck-down The localized reduction of a conductor’s width to allow it to be routed through tightly spaced patterns.

negative 1) (adjective) Describing an artwork, artwork master, or production master in which the intended conductive pattern is transparent to light, and the areas to be free from conductive material are opaque.

2) (noun) A reverse-image contact copy of a positive, useful for checking revisions of a PCB. If the negative of the current version is superimposed over a positive of an earlier version, all areas will be solid black except where changes have been made.

net An independent set of circuit nodes on a schematic that are connected together to define an isolated circuit. Each net is given a unique (alphanumeric) name to differentiate it from the other nets in the schematic.

net list An alphanumeric listing of symbols or parts and their connection points which are logically connected in each net of a circuit. A net list can be ‘captured’ (extracted electronically on a computer) from a properly prepared CAE schematic.

no-clean soldering A soldering process that uses a specially formulated solder paste that does not require the residues to be cleaned after solder processing.

node 1) An electrical junction connecting two or more component terminations. 2) An individual component termination (pin), test point, or I/O within a circuit net. A ‘cluster describes a set of nodes which are connected directly by a track; an ‘open node’ is a position at which a cluster may be accessed by a test probe.

nomenclature The decals and reference designators in epoxy ink on a printed circuit board: see legend.

non-eutectic Refers to an alloy which passes from a solid to a pasty state before passing to a fully liquid state during melt.

non-functional pad A land on an internal or external layer that is not connected to an active conductive pattern on that layer.

non-recurring cost The one-time (hopefully!) cost of design and development activities prior to starting production of a PCA.

non-wetting A condition where a surface has contacted molten solder, but the solder has not adhered to all of the surface, so that some base metal remains exposed. Non-wetting is caused by a physical barrier (intermetallic or oxide) between the surfaces to be joined so that the wetting forces are insufficient to overcome the surface tension of the solder, resulting in the solder balling up rather than flowing out over and attaching to the metal surface. Usually caused by oxidation and/or overheating the solder.