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GLOSSARY of Printed Circuits

by John Walt Childers, IPC-CID, Founder of Golden Gate Graphics

   SYMBOLS    A    B    C    D    E    F    G    H    I    J    K    L    M    N    O    P    Q    R    S    T    U    V    W    X    Y    Z   

Pronunciation Key

Formerly known as

GLOSSARY of Printed Circuit Design and Manufacturing

This glossary has key terminology in use in PCB design and manufacturing, with a smattering of electronics. The definitions were chosen so that their context would likely apply to reading material encountered by a PCB designer. Therefore, many of these terms will have other meanings not given here. See recommended dictionaries below.

This collection of terms came about as I, a PCB designer, ran across words and acronyms in my field for which meanings were hard to find. As I tracked them down, I made them part of this glossary. If you are a PCB designer, then this glossary could be a good place to start when you find a need to look up the meanings of words related to printed circuits or electronics.

TOP       N

Index to terms on this page:

naked   NAND   NC drill  
NC drill file   NECL   negative  
negative temperature coefficient   NEMA   net   netlist   NIPDAU   non-collapsing  
non-collapsing balls   node   NOR   no pullback pad  
non-solder-mask defined   np0   NPO   NPTH   NRE   NSMD pad   NTC   numerical control  

naked — (of a PCB) bare, not populated with components.

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NAND — Not AND. The logic function (or gate) whose value (or output) is the negation (inversion) of the AND of its arguments (inputs).

NAND flash memory The two main types of flash memory are named after the NAND and NOR logic gates. The individual flash memory cells exhibit internal characteristics similar to those of the corresponding gates. The NAND type is found primarily in memory cards, USB flash drives, solid-state drives (those produced in 2009 or later), and similar products, for general storage and transfer of data.

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NC drill Numeric controlled (computer controlled) drill machine. A machine used to drill the holes in a printed board at exact locations, which are specified in a data file. Also known as CNC (Computerized Numeric Controlled) drill machine.

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

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NECL — (NEK-əl)  Pronunciation Key  noun  [Electronics] Negative emitter-coupled logic, the original ECL technology.

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  1. 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.
  2. modifier . (Of a PCB image) Representing copper (or other material) as clear areas and absence of material as black areas. Typical of power and ground planes and solder mask.

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negative temperature coefficient — (NTC) occurs when the thermal conductivity of a material decreases with increasing temperature, typically in a defined temperature range. For most materials, the thermal conductivity will rise with increasing temperature. Most ceramics exhibit NTC behaviour.

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NEMA National Electrical Manufacturers Association

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net — A collection of terminals all of which are, or must be, connected to each other electrically. Also known as a signal.

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netlist — List of names of symbols or parts and their connection points which are logically connected in each net of a circuit. A netlist can be "captured" (extracted electronically on a computer) from a properly prepared CAE schematic. .

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NIPDAU — NIPDAU stands for Nickel-Palladium-Gold (based on the element abbreviations; plating for leads in RoHS compliant electronic components)

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non-collapsing — (NON-kə-LAP-sing)   Pronunciation Key  modifier  [Components]  (of BGA balls)
Not losing height during reflow soldering. The solder paste flows during soldering, but the ball maintains its size and shape. The non-collapsing balls are commonly the case when ball-pitch is 0.5 mm or less, where the land (pad) is larger than the ball to allow for via-in-pad technology and provide an adequate annular ring.

The solder mask can be the same size as the land. In some cases the land for fine pitch BGA’s is solder mask defined where the solder mask encroaches slightly over the land.

The solder mask defined land provides protection for any trace routing between the lands but the most significant benefit is to help secure the land to the PCB. During cell phone "drop testing," the BGA solder joint normally holds better than the land to the prepreg. Drop tests prove that the non-solder mask land will rip from the PCB before the solder joint breaks. So the solder mask defined land is secured better to the PCB for drop testing.

Hausherr, Tom. Blog: PCB Design Perfection Starts in the CAD Library Part 9, section en-titled "BGA Components," Jan 21, 2011. Mentor Graphics, A Siemens Business, 8005 Boeckman Rd, Wilsonville, OR 97070. (URL no longer available. Before being acquired by Siemens, Mentor Graphics granted John Walt Childers permission to use segments of Mr. Hausherr's blog.)

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non-collapsing balls — BGA balls which do not collapse. These are commonly the case when ball-pitch <= 0.5 mm. See non-collapsing.

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node — A pin or lead which will have at least one wire connected to it. In a netlist, a node is described by a component reference desginator together with a pin number.

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NOR — Not OR. The logic function (or gate) whose value (or output) is the negation (inversion) of the OR of its arguments (inputs).

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no pullback pad — Refers to the pads on an LCC having metal exposed on the edge of the body of the package. (constrast with pullback pad.) The type, pullback or no pullback, effects the solder stencil requirements.

Detailed and specific information concerning PCB layout, fabrication, and mounting an leadless leadframe package (LLP) package, including solder stencil consideratons regarding pullback versus no pullback pads, is available in the Texas Instruments (nee National) application note AN-1187.

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non-solder-mask defined — Expansion of the opening of solder mask beyond the edges of a pad. Thus, the copper of the pad itself defines how much copper is exposed to solder or air. In PCB design, this is the most common relationship of solder mask to pad. (Contrast with solder-mask-defined. For vias, contrast with tented via.) Such a pad is sometimes called a "land-defined land".

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np0 — (IN-PEE-ZIR-oh)  Pronunciation Key  modifier  [Components]NPO (Could be shown lower case to emphasize the 0 is zero, a number, not a letter.) Negative-Positive zero, is the designator for a class of dielectric materials (EIA Class 1 dielectric) used in ceramic capacitors whose capacitance is affected only 1/2 % by temperature change. (aka c0g). See Wikipedia Class 1 ceramic capacitors and CapSite 2006 Ceramic Capacitors

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NPO — (IN-PEE-OH)  Pronunciation Key  A misspelling of np0, q.v.

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NPTH — Non-Plated Through Hole.

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NRE — Non-Recurring Engineering (costs). [Stammtish Beau Fleuve Acronyms]

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NSMD pad [PCB Manufacturing] Non-Solder-Mask Defined pad. This is the normal case where all of the copper area of a land is exposed and the solder mask opening is larger than that.

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NTC — Negative Temperature Coefficient.

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numerical control — Control of a system or device by direct input of data in the form of numbers, letters, symbols, words, or a combination of these forms. It is a principal element of computer-integrated manufacturing, particularly for controlling the operation of machine tools. NC is also essential to the operation of modern industrial robots. numerical control

Motion pictures: Numerical control is also used in "motion control photography," which made the special effects possible and was used for the first time in history in the filming of the original Star Wars. Motion control photography was a brand new technology created specifically for that film. This technology is described in the documentary film Industrial Light & Magic: Creating the Impossible directed by Leslie Iwerks and written & edited by Iwerks and Jeff Stephenson.

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Alphabetizing Method

Terms that begin with a symbol or a digit are placed in the SYMBOLS page. Terms that contain digits within them are alphabetized as if the numeric characters were spelled in English.

Terms with two or more words are alphabetized "dictionary style." They are alphabetized as though the spaces between the terms have been removed.
   If there are other characters in the term, such as a slash (/), dash (-) or plus sign (+), these are treated the same as spaces and ignored for the purpose of alphabetizing.

Example Printed Boards

Click for Examples of PCBs designed by Golden Gate Graphics

References and Dictionaries

Modern Dictionary of Electronics by Rudolf F. Graf

This is the best, most usable dictionary for electronics, because its definitions help you grasp the terms and therefore the subject. Lesser dictionaries define electronics terms with even more difficult technical jargon, leading one into endless"word chains." Not this one.
You can buy the Modern Dictionary of Electronics new or used via the Internet.

Graf, Rudolf F. Modern Dictionary of Electronics. Newnes, 1999.

The Random House Dictionary of the English Language, Unabridged, 2nd Edition

You need a big, comprehensive dictionary. Get this one. Despite being a big dictionary, The Random House has great definitions, quick to grasp.

Although out of print, as of 2022 you could still buy a great used copy online for $40 including shipping or possibly for much less. Two versions are available of the 2nd Edition, Unabridged:

I have no idea what the difference is for the deluxe edition, but there seem to be fewer copies of it available in 2020 than the regular edition. I'm sure they both have the same set of definitions. My copy has both ISBNs listed in the front matter, and it is the regular edition.

Flexner, Stuart Berg, and Leonore Crary Hauck, editors. The Random House Dictionary of the English Language. Unabridged, 2nd Edition, Random House, 1987.

Golden Gate Graphics in an official Altium Service Bureau
Golden Gate Graphics is an official Altium Service Bureau