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GLOSSARY of Printed Circuits

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

   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

Golden Gate Graphics in an official Altium Service Bureau

Golden Gate Graphics is an official Altium Service Bureau

Terms that contain digits 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 (/), these are treated the same as spaces and ignored for the purpose of alphabetizinig.


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Index to terms on this page:

ablation   active component   active heatsink   AFE   ALN   alumina   analog circuit   anode   ANT   antipad   aperture  
aperture list   aperture table  
aperture wheel   ARM   artwork   ASCII   ASCII text   assembly   assembly drawing   assembly house   ASTM   AT cut   ATC   ATE   AWG   auto router  



ablation — (u-BLAY-shən)  Pronunciation Key  noun  [PCB Manufacturing] (In the context of "laser ablation" in the making of blind and buried vias) Vaporization.
A PCB designer should be aware that a hole caused by ablation has an inverted cone shape rather than a cylindrical shape, as would be the case with a hole drilled with a bit. Partly because of this, a laser-ablated hole can not have an aspect ratio greater than 1:1. In contrast, a drilled hole can have an aspect ratio of 10:1 or greater (or less for some board houses). Therefore, laser-ablated holes are only feasible in build-up manufacturing. The padstack for a laser-ablated via can have a smaller pad on the tapered end than on the large (the starting point) end. This fact can be helpful in designing a space transformer.
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active component  — (AK-təv KOM-poh-nənt) Pronunciation Key

  1. noun [Electronics] A component which adds energy to the signal it passes.
        
  2.  
  3. noun [Electronics] A device that requires an external source of power to operate upon its input signal(s).
        
  4.  
  5. noun [Electronics] Any device that switches or amplifies by the application of low-level signals.
    Examples of active devices which fit one or more of the above definitions: transistors, rectifiers, diodes, amplifiers, oscillators, mechanical relays and almost all IC's (Contrast with passive component.)   
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active heatsink — (AK-iv HEET-seenk)  Pronunciation Key  noun  [Components] A heatsink which uses an applied energy to operate.
Examples are 1) a mini-fan attached to a chip package and 2) a TEC with a fan to blow away generated heat.
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AFE — (AY-EF-EE)  Pronunciation Key  noun  [Electrical Engineering] Analog Front End

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ALN — (AY-EL-IN)  Pronunciation Key  noun   [Semi-conductor Manufacturing] Aluminum Nitride, a compound of aluminum with nitrogen.
Ceramic substrate material used for heat dissipation.
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alumina — A ceramic used for insulators in electron tubes or substrates in thin film circuits. It can withstand continuously high temperatures and has a low dielectric loss over a wide frequency range.  Aluminum oxide (Al 2 O 3 )
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analog circuit — A circuit in which the output varies as a continuous function of the input, as contrasted with digital circuit.
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anode  — (AN-ohd) Pronunciation Key

  1. noun [Electronics] The positive element, such as the plate of a vacuum tube. The element to which the principal stream of electrons flows.
        
  2.  
  3. noun [Electronics] In a cathode-ray tube, the electrodes connected to a source of positive potential.
     These anodes are used to concentrate and accelerate the electron beam for focusing.   Graf_ Rudolf_F_MDE_Newnes_1999
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ANT — (ANT)  Pronunciation Key  noun  [Communications Technology] Adaptive Network Technology. A radio transceiver protocol, ANT is a proprietary wireless sensor network technology featuring a wireless communications protocol stack that enables semiconductor radios operating in the 2.4 GHz Industrial, Scientific and Medical allocation of the RF spectrum ("ISM band") to communicate by establishing standard rules for co-existence, data representation, signalling, authentication and error detection.
ANT is ported to a semiconductor transceiver from a specialist manufacturer (typically Nordic Semiconductor of Oslo, Norway) for practical implementations. ANT is characterized by a low computational overhead, and high efficiency that results in low power consumption by the radios supporting the protocol.
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antipad — (ANT-tee-pad)  Pronunciation Key  noun  [PCB Manufacturing] The diameter of the copper free area around a plated-through hole (PTH) in a power plane, which electrically isolates the PTH from the power plane.
In a negative image power plane, an antipad is created by placing a disc shaped object larger than the PTH and centered on it in the power plane artwork. Since this is a negative image, which means anything black on a transparent flim photoplot represents an absence of copper, the object forces a keepout of copper in the power plane as manufactured in the PCB. The drill dia + 0.020 in. (20 mils or 0.5 mm) is an acceptable ground rule for the antipad land size, although some board houses will require more than this. To specify the size of the antipad, the padstack can be edited for that hole, either in the footprint of the part in the PCB library or directly in the PCB file. In advanced PCB design packages such as Altium Designer, rather than edit the padstack, one creates a design rule that automatically creates the antipad. The easiest way to alter the size of an antipad is to edit the power plane clearance distance.

power plane clearance


Altium design rules - power plane clearance

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aperture  — (A-pə-chər) Pronunciation Key

  1. noun [Photoplotting] An indexed shape with a specified x and y dimension, or line-type with a specified width, used as a basic element or object by a photoplotter in plotting geometric patterns on film.
    The index of the aperture is its Position (a number used in an aperture list to identify an aperture) or D code     
  2.  
  3. noun [Photoplotting] A small, thin, trapezoidal piece of plastic used to limit and shape a light source for plotting light patterns on film, and mounted in a mechanical disk called an "aperture wheel," which in turn is mounted on the lamp head of a vector photoplotter. An aperture is mostly opaque, but with a transparent portion that controls the size and shape of the light pattern.
     A vector photoplotter plots images from a CAD file. It plots on photographic film in a darkroom. It plots lines by drawing each line with a continuous lamp shined through an annular-ring aperture. It creates shapes (or pads) by flashing the lamp through a specially sized and shaped aperture.   
  4.  
  5. noun [Photoplotting] A line of textual data in an aperture list describing the index names (D code and position), the shape, the usage(flash or draw) and the X and Y dimensions of an aperture.
     Some aperture lists leave out certain of those types of data. For example, laser photoplotters don't need to know whether an aperture is a flash or draw, so a modern-day aperture list might leave that datum out.   
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aperture list  — (A-pə-chər list) Pronunciation Key

  1. noun [Photoplotting] An ASCII text data file which describes the size and shape of the apertures used by a photoplotter for any one photoplot.
        
  2.  
  3. noun [Photoplotting] A print-out of this file.
        
  4.  
  5. noun [Photoplotting] A binary version of this file. [Also called "aperture table."]
        

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aperture table — See aperture list.
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aperture wheel — A component of a vector photoplotter , it is a metal disk having cut-outs with brackets and screw holes arranged near its rim for attaching apertures. Its center hole is attached to a motorized spindle on the lamp head of the photoplotter. When a D code denoting a particular position on the wheel is retreived from a Gerber file by the photoplotter, the wheel is caused to rotate so that the aperture in that position is placed between the lamp and the film.

In preparation for a photoplotting, the aperture wheel is set up by a technician who reads a printed aperture list , selects the correct aperture from a set of them stored in a box with compartments and, using a small screw driver, installs the aperture onto the position on the wheel which is called for on the list. This process is subject to human error and is one of the disadvantages of vector photoplotters as compared with laser photoplotters.

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ARM — (AHRM)  Pronunciation Key  noun  [Electronics] Advanced RISC Machine. RISC stands for Reduced Instruction Set Computing.
The ARM technology is licensed by ARM Holdings
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artwork — Artwork for printed circuit design is photoplotted film (or merely the Gerber files used to drive the photoplotter), NC Drill file and documentation which are all used by a board house to manufacture a bare printed circuit board. See also Valuable Final Artwork.
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ASCII — American Standard Code for Information Interchange.   A text and control-code character set used in computers.  Pronounced "ASS-key."  

(Note:  The following description is excerpted from "FOLDOC," Free Online Dictionary of Computing. The links in this definition point to FOLDOC and will take you off this site unless you right-click on the link and select "Open link in new tab" .)

ASCII is the basis of character sets used in almost all present-day computers. US-ASCII uses only the lower seven bit s (character points 0 to 127) to convey some control codes , space, numbers, most basic punctuation, and unaccented letters a-z and A-Z. More modern coded character sets (e.g., Latin-1 , Unicode ) define extensions to ASCII for values above 127 for conveying special Latin characters (like accented characters, or German ess-tsett), characters from non-Latin writing systems (e.g., Cyrillic, or Han characters ), and such characters as distinct open- and close-quotation marks (“ and ”), ¾ and ®.

The complete ASCII character set known as "Latin-1", an extension to 256 characters of the US-ASCII 128-character set, has been provided online by Paul Lutus at Arachnoid.com.
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ASCII text — A thoroughly unoffical subset of US-ASCII which contains the space character, numbers, most basic punctuation, and unaccented letters a-z and A-Z, but lacks the control codes.
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assembly

  1. The process of positioning and soldering components to a PCB.  
  2. Act or process of fitting together parts to make a whole.
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assembly drawing — A drawing depicting the locations of components, with their reference designators , on a printed circuit. Also called "component locator drawing."
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assembly house — A manufacturing facility for attaching and soldering components to a printed circuit. Aka assembler and also CM, for contract manufacturer.
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ASTM — American Society of Testing and Materials.   http://www.astm.org/index.shtml
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AT cut — (AY-TEE-KUT)  Pronunciation Key  noun  [Crystallography] (Of piezoelectric crystals) One of the designations for the orientation of the piezoelectric crystal plate with respect to the axes of the crystal.
The AT cut results in a crystal with stable resonant frequency at or close to room temperature. For a high temperature environment, stress-compensated (SC) crystals are available with a special cut that minimizes the frequency changes due to temperature gradients. Graf_ Rudolf_F_MDE_Newnes_1999
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ATC — (AY-TEE-SEE)   Pronunciation Key   noun  [Physical Testing] Accelerated Thermal Cycle (or Cycling), a product reliability test.
Accelerated thermal cycling is accomplished by raising and lowering the temperature of a test object to extremes and more rapidly than would be found in nature or industrial environments. An example: Accelerated Thermal Cycling (ATC) could be carried out between 0˚C and 100˚C with 10 minute ramps, a 10 minute cold dwell and 10-minute hot dwell or 60-minute hot dwell. Test frequencies could be 16 and 36 cycles/day for the 60-minute and 10-minute dwell test profiles respectively. Clech_Jean-Paul_AFTCTELA_EPSI_2005
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ATE — Automatic Test Equipment. (See also DUT.) .
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AWG — American Wire Gauge.  A PCB Designer needs to know diameters of wire gauges to properly size E-pads. The American Wire Gauge, formerly known as the Brown and Sharpe (B + S) Gauge, originated in the wire drawing industry.  The gauge is calculated so that the next largest diameter always has a cross-sectional area that is 26% greater.
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auto-router — automatic router, a computer program that routes a PC board design (or a silicon chip design) automatically.
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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.

Citation:
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 2020 you could still buy a great used copy online for $30 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.

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

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