Electrical Engineering Searching Best Practices

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Electrical engineering is traditionally defined as the technology of electricity, especially the design and application of circuitry and equipment for power generation and distribution, machine control, and communications. This broad definition encompasses other categories including Computer and Information Sciences and Electrical Communications.

Usually an Electrical Engineering search will focus on subject matter related primarily to the circuitry or electrical components of a system. This seemingly narrow definition still embodies everything from electrical systems (US class 361) to electrical connectors (US class 439).

Obstacles Facing the Searcher

One obstacle facing the Electrical Engineering searcher is the identification of the optimum search resource. In many cases, it can be difficult to determine whether patent or non-patent literature will be the optimum source of pertinent prior art. While patents are more typically focused on the applications of a newly discovered technology, the basic research behind such new technology can often be found in abundance within the scientific literature but with sparse mention in the patent literature. Therefore, for relatively new and emerging technologies, such as Microelectrical Mechanical Systems (MEMS), non-patent literature may be more heavily relied upon as the patent documentation in those fields may not be as developed as in older fields.

In cases where a patent searcher is uncertain as to whether patent or non-patent literature is the optimum source it is useful to query a database which covers both sources, such as Thomson Innovation, using keywords associated with the technology of interest and to do a quick survey to see whether patents or non-patent sources appear more frequently. Alternately, a hit comparison may be performed using common keywords in a patent exclusive database versus a non-patent exclusive database. Time for patent versus non-patent searching can be distributed in accordance with the results of such comparisons.

Searching Patent Documents

Patent searching in the art of Electrical Engineering is normally done with a combination of keyword text searching and image-based searching. Search tools that can perform both of these types of searches well are often preferred by searchers in this field.

Figure or picture-based searching is often necessary when performing electrical circuit searches. This is because it is virtually impossible at times to develop full text search strings to encompass the characteristics of a circuit. A couple examples of good tools to use for this reason include EAST and Google Patent Search.

Searching Non-Patent Literature

For non-patent literature searching, Google Scholar is preferred by many searchers because of its easy-to-use interface and ability to search a large number of journals simultaneously. It is also the easiest source from which to retrieve articles in PDF (Portable Document Format). Additionally, Google Scholar’s "cited by" (citation indexing) has been cheered as a powerful feature similar to those previously only available in subscription-based tools such as Scopus and Thomson ISI Web of Science.[1]

IEEE (Institute of Electrical and Electronics Engineers) tools such as IEEE Xplore are also a popular non-patent literature resource in this field. The IEEE databases contain thousands of articles covering all facets of electrical engineering and computer science. Note that IEEE publications are indexed within Google Scholar and will appear in results in that system as well.

Besides IEEE, there are several other non-patent databases that are relevant to the Electrical Engineering searcher. These include Inspec, ISI Web of Science, and Compendex. These databases can be accessed through several sources, a few of the major ones being Thomson Dialog, Engineering Village, and Questel.

Specific Search Strategies

These search strategies are examples of specific best practices that can be applied during the course of a search in the area of Electrical Engineering. These are steps to be taken in addition to accepted search practices that apply to all searches. For a more general progression of search steps, please see the General Searching article.

  • If unsure which patent search tool to use, start with one that provides both powerful keyword searching and fast image searching.
  • Look up any element abbreviations so that both the abbreviation and the full word can be searched. For example, in a search that involves silicon, one should also search for its abbreviation, Si. This also goes for chemical compounds, such as Silicon Dioxide, abbreviated SiO2.
  • If the searcher desires clarification of terms or features, a good resource for quickly gaining knowledge of a Electrical Engineering related technology is Wikipedia. Google can also be used to identify synonyms for electrical components. For example, a transistor can also be called an 'amplifier' or an 'electrically controlled switch'. Google and Wikipedia are both useful for finding synonyms to use in a search.
  • For newer technological arts such as Microelectrical Mechanical Systems (MEMS), the patent literature will likely have fewer teachings than non-patent literature sources. NPL resources such as those available from IEEE, Inspec, Knovel, and Google Scholar can be especially useful when searching newer technologies, due to the relative lack of patent documentation available.
  • Keyword searching combined with citation-based relevancy ranking such as that in Google Patent Search can be valuable to the Electrical Engineering searcher when the goal of the search is to find a handful of highly relevant prior art, rather than an exhaustive list of every piece of prior art.

Key Classification Areas

257 Active Solid State Devices
361 Electrical Systems and Devices
381 Electrical Audio Signal Processing Systems and Devices
429 Batteries and Fuel Cells
438 Semiconductor Device Making
439 Electrical Connectors
... See link in the header of this table for full class definitions

IPC on WIPO / ECLA in espacenet
H01B Cables
H01C Resistors
H01F Magnets, Inductances, Transformers
H01L Semiconductor Devices
H01H Electric Switches
H02H Emergency Protective Circuits
H01M Batteries
H01R Electrical Connectors
... See links in the header of this table for full class definitions

Japanese F-Terms
5J100 Control of Amplification and Gain Control
5E087 Connector Housings and Securing of Contact Members
5B058 Card Readers and Writers; Peripherals
5E021 Details of Coupling Devices
5E077 Multi-conductor connections (e.g., printed circuit boards)
5E336 Structures for Mounting of Electric Components on Printed Circuit Boards
... See link in the header of this table for full class definitions


For further reading, searchers should reference the corresponding best practices articles covering physical sciences and electrical communications. Due to some overlap in the fields, the best practices and sources disclosed in those articles may also be applicable to Electrical Engineering searches.


  1. Google Scholar Wikipedia entry. Wikipedia, http://en.wikipedia.org/wiki/Google_Scholar.

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