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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       H

Index to terms on this page:

hard copy   HASL   H-bridge   HDMI   header  
he, him, his, himself   High frequency   high melt   HMSOP   hole   HPGL   HSA   HSMC   HTQFP  
HTML escaping   HVQFN   hybrid  

hard copy — A printed or plotted form of an electronic document (computer data file).

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HASL — (HA-səl)   Pronunciation Key  modifier  [PCB Manufacturing] (of a PCB finish) Hot Air Solder Leveling (or Leveled).
   During fabrication and after solder mask is applied, the PWB is lowered through a "hot air knife" fixture and dipped in a molten solder bath. This coats all the copper that hasn't been covered up by solder mask. These are the conductors that will get solder applied to them during assembly. As the PWB is drawn back up through the knife fixture, the hot air stream is turned on and blown forcefully across all sides of the board. Were talking hot here. The air is hot enough to melt solder. This removes excess solder from the exposed copper, leaving a thin coat that is just right for the upcoming assemly processes and to protect the copper from oxidation. This makes the solder coat on pads relatively flat, or level.

Vertical HASL process
Vertical HASL process

Source: Hot Air Solder Leveling in the Lead-free Era by Keith Sweatman, Nihon Superior Co., Ltd., Osaka, Japan. HASL is just one process among many in the fabrication of a printed board. I encourage you to take a tour of a board house. If you can't visit one in person, you can take the step-by-step video tour of PCB manufacturer Saturn Electronics Corporation, a metro Detroit board house. This is a great, educational video. It details the various processes involved in the fabrication of a bare printed circuit board. Thank you, Saturn Electronics!

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H-bridge — An H-bridge is an electronic circuit that switches the polarity of a voltage applied to a load. These circuits are often used in robotics and other applications to allow DC motors to run forwards or backwards.
[1: Al Williams (2002). Microcontroller projects using the Basic Stamp (2nd ed.). Focal Press. p. 344. ISBN 978-1-57820-101-3.]
Most DC-to-AC converters (power inverters), most AC/AC converters, the DC-to-DC push–pull converter, isolated DC-to-DC converter
[2: "11kW, 70kHz LLC Converter Design for 98% Efficiency" ] most motor controllers, and many other kinds of power electronics use H bridges. In particular, a bipolar stepper motor is almost always driven by a motor controller containing two H bridges. H-bridges are available as integrated circuits (example dual H-bridge IC: Allegro_MicroSystems_LLC-A4954ELPTR-T), or can be built from discrete components.
The term H-bridge is derived from the typical graphical representation of such a circuit.

Structure of an H-bridge (highlighted in red)
Structure of an H-bridge (highlighted in red)
An H-bridge is built with four switches (solid-state or mechanical). See figure above. When the switches S1 and S4 are closed (and S2 and S3 are open) a positive voltage is applied across the motor. By opening S1 and S4 switches and closing S2 and S3 switches, this voltage is reversed, allowing reverse operation of the motor.
Using the nomenclature above, the switches S1 and S2 should never be closed at the same time, as this would cause a short circuit on the input voltage source. The same applies to the switches S3 and S4. This condition is known as shoot-through. {Wikipedia:}

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HDMI — High Definition Multimedia Interface

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he, him, his, himself — The defintion used most often on this website is: A human being, name and sex unspecified.

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header — The portion of a connector assembly which is mounted on a printed circuit.

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High frequency — High frequency (HF) is the ITU designation[1] for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one hundred meters). The HF band is a major part of the shortwave band of frequencies, so communication at these frequencies is often called shortwave radio. Because radio waves in this band can be reflected back to Earth by the ionosphere layer in the atmosphere these frequencies are suitable for long-distance communication across intercontinental distances and for mountainous terrains which prevent line-of-sight communications. The band is used by international shortwave broadcasting stations (3.95–25.82 MHz), aviation communication, government time stations, weather stations, amateur radio and citizens band services etc.

Table of High Frequency Wavelengths 80 to 10 meters

80 meters 3.5-4.0 MHz (3500-4000 kHz)
60 meters 5 MHz region
40 meters 7.0-7.3 MHz Considered the most reliable all-season DX band. Popular for DX at night DX = telegraphic shorthand for "distance" or "distant".
30 meters 10.1-10.15 MHz RTTY
20 meters 14.0-14.35 MHz Considered the most popular DX band
17 meters 18.068-18.168 MHz
15 meters 21-21.45 MHz generally a daytime band
12 meters 24.89-24.99 MHz Best long distance (e.g. across oceans) activity is during solar maximum; during periods of moderate solar activity the best activity is found at low latitudes.

Wikipedia High Frequency amateur radio frequency allocations
30 meters – 10.1–10.15 MHz – a very narrow band, which is shared with non-amateur services. It is recommended that only Morse Code and data transmissions be used here, and in some countries amateur voice transmission is actually prohibited. For example, in the US, data, RTTY and CW are the only modes allowed at a maximum 200 W peak envelope power (PEP) output. Not released for amateur use in a small number of countries. Due to its location in the centre of the shortwave spectrum, this band provides significant opportunities for long-distance communication at all points of the solar cycle. 30 meters is a WARC band. "WARC" bands are so called due to the special World Administrative Radio Conference allocation of these newer bands to amateur radio use. Amateur radio contests are not run on the WARC bands.

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high melt — having a high melting point.

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HMSOP — Heat-sink MSOP or Heat-Sink Micro (or Mini) Small Outline Package. The heat-sink is an exposed die-attached pad under the body. Texas Instruments' code for this package is DGQ.

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hole — In a semiconductor, the term used to describe the absence of an electron; has the same electrical properties as an electron except that it carries a positive charge.   [Graf, Rudolf F. Modern Dictionary of Electronics. Newnes, 1999]

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HPGL — Hewlett-Packard Graphics Language, a text-based data structure of pen-plot files which are used to drive Hewlett-Packard pen plotters. Although Hewlett-Packard no longer makes pen plotters, the large-format dot matrix printers which replaced them can also be driven by HPGL.

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HSA — Hall effect Switch

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HSMC — High Speed Mezzanine Card, a designation used by Altera.

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HTQFP— Heat-sinkTQFP. Heat-Sink Thin Quad Flat pack. Aka TQFP_EP (TQFP Exposed Pad). Aka, by Analog Devices, SV-[lead count]-3.

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HTML escaping — Converting HTML tag characters or other special characters occuring in an HTML text into HTML code equivalents so that the tag characters are rendered by the Internet browser as the literal character; therefore, they can not become invisible, as might be the case for tag characters, and can not be interpreted by the browser engine as special-function HTML code or PHP or other code.
HTML escaping typically makes these replacements:
< is converted to &lt;
> is converted to &gt;
' (apostrophe or single quote) is converted to &#39; or &apos;
" (double quote) is converted to &quot;
& is converted to &amp;

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HVQFN — Heat sink Quad Flat Package, Heatsink Very-thin Quad Flat-pack No-leads (HVQFN) is a package with no component leads extending from the IC. Pads are spaced along the sides of the IC. Underneath the package is an exposed DAP that can be used as a heatsink and is usually connected to ground.

HVQFNis a term used by NXP Semiconductors. The H at the beginning is really rather unnecessary, because most QFN's have a die-attached paddle.

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hybrid — (HAHY brid)  Pronunciation Key  noun  [Component Manufacturing] The word hybrid is defined as “the offspring resulting from crossbreeding." Many would agree that this is an apt description for the species of electronic entities known as hybrids, which combine esoteric mixtures of interconnection and packaging technologies. In electronic terms, a hybrid consists of a collection of components mounted on a single insulating base layer called the substrate. A typical hybrid may contain a number of packaged or un-packaged integrated circuits and a variety of discrete components such as resistors, capacitors, and inductors, all attached directly to the substrate.
Connections between the components are formed on the surface of the substrate; also, some components such as resistors and inductors may be fabricated directly onto the surface of the substrate. [Bebop to the Boolean Boogie (An Unconventional Guide to Electronics) by Clive Maxfield]

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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