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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       W

Index to terms on this page:

wafer     WEEE  
wet solder mask   white space   Wi-Fi   WiMAX   WIP   wire  
wire bonding   wirewound inductors  
wire wrap area   wiring   working copy   WP   WQFN   WSN   WSON  

wafer — See silicon wafer .

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WEEE — Waste from Electric and Electronic Equipment (directive), combined from W and EEE.

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wet solder mask — Applied by means of distributing wet epoxy ink through a silk screen, a wet solder mask has a resolution suitable for single-track design, but is not accurate enough for fine-line design. Therefore, it has been obsolete for decades.

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white space — blank or space or other characters that are invisible in printed documents, but can be shown in open word processor documents if "Show hidden characters" option is chosen. Some PCB design CAD and CAE software can't handle white space in certain kinds of data. But Altium Designer handles white space with aplomb.

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Wi-Fi — WIreless high-FIdelity communication technology that conforms to IEEE standard 802.11b.

A family of radio technologies commonly used for wireless local area networking (WLAN) of devices. It is based on the IEEE 802.11 family of standards. Wi-Fi is a trademark of the Wi-Fi Alliance, which restricts the use of the term Wi-Fi Certified to products that successfully complete interoperability certification testing.[2][better source needed] The Wi-Fi Alliance includes 3Com (now owned by HPE/Hewlett-Packard Enterprise), Aironet (now owned by Cisco), Harris Semiconductor (now owned by Intersil), Lucent (now owned by Nokia), Nokia and Symbol Technologies (now owned by Zebra) Technologies).[3]

Wi-Fi uses multiple parts of the IEEE 802 protocol family and is designed to seamlessly interwork with its wired sister protocol Ethernet. Devices that can use Wi-Fi technologies include desktops and laptops, smartphones and tablets, smart TVs, printers, digital audio players, digital cameras, cars and drones. Compatible devices can connect to each other over Wi-Fi through a wireless access point as well as to connected Ethernet devices and may use it to access the Internet. Such an access point (or hotspot) has a range of about 20 meters (66 feet) indoors and a greater range outdoors. Hotspot coverage can be as small as a single room with walls that block radio waves, or as large as many square kilometres achieved by using multiple overlapping access points.

Depiction of a device sending information wirelessly to another device, both connected to the local network, in order to print a document.

The different versions of Wi-Fi are specified by various IEEE 802.11 protocol standards, with the different radio technologies determining the ranges, radio bands, and speeds that may be achieved. Wi-Fi most commonly uses the 2.4 gigahertz (12 cm) UHF and 5 gigahertz (6 cm) SHF ISM radio bands; these bands are subdivided into multiple channels. Each channel can be time-shared by multiple networks. These wavelengths work best for line-of-sight. Many common materials absorb or reflect them, which further restricts range, but can tend to help minimise interference between different networks in crowded environments. At close range, some versions of Wi-Fi, running on suitable hardware, can achieve speeds of over 1 Gb/s (Gigabit per second).

Wi-Fi is potentially more vulnerable to attack than wired networks because anyone within range of a network with a wireless network interface controller can attempt access. Wi-Fi Protected Access (WPA) is a family of technologies created to protect information moving across Wi-Fi networks and includes solutions for personal and enterprise networks. Security features of WPA have included stronger protections and new security practices as the security landscape has changed over time.

[WiFi without the hyphen would be incorrect spelling]
Source: Wikipedia Wi-Fi

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WiMAX — Worldwide Interoperability for Microwave Access is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide multiple physical layer (PHY) and Media Access Control (MAC) options.

The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard, including the definition of predefined system profiles for commercial vendors. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL". IEEE 802.16m or WirelessMAN-Advanced was a candidate for the 4G, in competition with the LTE Advanced standard.

WiMAX was initially designed to provide 30 to 40 megabit-per-second data rates,[3] with the 2011 update providing up to 1 Gbit/s for fixed stations.

The latest version of WiMAX, WiMAX release 2.1, popularly branded as/known as WiMAX 2+, is a smooth, backwards-compatible transition from previous WiMAX generations. It is compatible and inter-operable with TD-LTE.

Source: Wikipedia - WiMAX

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WIP — Work In Progress.  

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wire — Besides its usual definition of a strand of conductor, wire on a printed board also means a route or track.

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wire bonding — The method used to attach very fine wire to semiconductor components ( dice ) to interconnect these components with each other or with package leads.  The wires might be 1 to 2 mils in diameter and made of aluminum containing 1% silicon.

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wirewound inductors — Wirewound inductors are those formed by wrapping wire around a magnetic core of some type, and which have no distinguishing feature which would cause them to be categorized otherwise. The bulk of the general-purpose inductors available are of this type. They are relatively inexpensive and easy to produce, and as such are favored where large inductance values or current handling capability are called for, a high degree of precision isn't particularly important, and cost is a factor.
More information at Digi-Key TechForum:
Fixed Inductors (Scroll down to heading "Wirewound.")

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wire wrap area — A portion of a printed board riddled with plated-through holes on a 100-mil grid. Its purpose is for accepting circuits which may be found necessary after a PWB has been manufactured, stuffed , tested and debugged.

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wiring noun. The act of creating a conductive channel from one terminal to another. This can be a metal wire proceeding through space or a printed conductor laid out on a PWB.

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working copy [Apache Subversion] A local copy of a Subversion repository. A user makes changes to his working copy, not directly to the repository. Once he is ready to publish his changes, he uses a Subversion client to commit (q.v. and loosely synonymous with "upload") his working copy to the repository. Synonym: sandbox.

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WP — Write Protect, a pin name and description used in serial interfaces.

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WQFN — The W in WQFN stands for Very Very Thin (0.8mm in maximum height), so this is a Very Very Thin Quad Flat No Lead package. Contrast with VQFN, which is Very Thin (0.9mm) and with UQFN (micro QFN - 0.5mm). Alternatively, WQFN and UQFN are also known as TQFN and UTQFN.

Reference: Texas Instruments - Quad Flat No Lead (QFN)

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WSN — Wireless Sensor Network

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WSON — Very-very-thin Small Outline No-lead, a PCB component footprint. "Small outline" implies that this has a pin configuration described as dual rather than quad. The "W" evidently stands for two V's with the T for thin understood. The thickness (component height) meant by "Very very thin" is 0.8 mm maximum height.

See downloadable PDF example WSON mechanical drawing from Silicon Storage Technology (now Microchip).

An example acronym could be "WSON-8" or "8-WSON,"s; either of which would mean an 8-contact WSON. There would be 8 signals possible. Add to that the metal bottom exposed paddle and the total number of connections becomes 9.

Footprint naming convention that incorporates dimensions

IPC has developed a standard for naming footprints: IPC-7351B Land Pattern Naming Convention. A proposal for IPC-7351C has been offered by Tom Hausherr of PCB Libraries. IPC-7351C hasn't yet been finalized, but I use Tom's proposed convention because it includes lead and thermal pad   dimensions. The naming convention for a WSON would be structured as a Small Outline No-lead:

SON + Pin Qty. + P Pitch _ Body Length X Width X Height + L Lead Length X Width + T Thermal Pad Length X Width

Dimensions in the naming convention are 100th millimeter. So to get that number, multiply the metric dimension in a mechanical drawing by 100. "Pin Qty." in this naming convention includes the signal pins plus the thermal pad.

Here is an example name for a WSON with 1.27mm [50 mil] terminal pitch, 8 signal pins with body dimensions of 5.00 mm length X 6.00 mm width x 0.80 mm maximum height and with metal terminals (aka " leads") size of 0.63 mm X 0.42mm and with an exposed paddle size of 4.00 mm length X 3.40mm width:

In this system, width is defined as the body dimension across the tips of the metallized contacts and length as the other horizontal dimension, thus width can be greater than length as it is here.

I use a name based on the Library Expert Land Pattern Naming Convention by Tom Hausherr . To that name, I add the manufacturer's acronym as a prefix. This makes it easier to search on and find similar parts in a footprint library. Acronym + Signal Pin Qty_Name Convention

The above example with the prefix added becomes:


Thus you get a footprint name that is easy to classify and find in a library and that identifies a dimensionally unique footprint by its name alone. You do not have to take measurements to see whether it matches the specifications in the component datasheet.

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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.

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