No matter how good Google search algorithm is, a purely mechanical algorithm can't always determine which sites are really useful and which are not. In addition, no search algorithm can know exactly what kind of info you are looking for. We all know that general purpose search engines bring up a lot of junk.
To address these issues Google recently launched Custom Search Engine (CSE) program which enables you to enhance your search by using human expertise and by specifying what type of info you are looking for. Particularly, my content is intented to improve your search experience in topics related to electrical generators and power electronics/SMPS.
EXAMPLES. Say, you want to choose a home generator and looking for something to start with. If you select my Guides/Reviews category, on the first search results page among other buyer's guides you will find a link to a very handy Consumer Reports' rating of generators. Otherwise, with a regular Google search this link is not among the top search results.
Alternatively, if you are looking for physical principles of electric generators you may want to eliminate commercial and advertising sites which represent more then half of the top results in "electric generator" query. Even if you try a more specific query like "how electric generator works", many relevant pages are still not at the top. Why? Because a search engine goes mainly by keywords you entered- obviously it does not know how generators work. Many web pages that describe in depth generator theory just do not use all these terms and won't show up in your top results. They do use more important terms though- you can't really describe generator's operation without using such words as Faraday, induction or magnet. That's why these terms are added to my "Generators/Physical principles" label. If you select this label, they will be automatically added in background to your query as additional search terms. This will make your refined search results more relevant and will weed out unrelated pages. In addition to this, web pages that I've personally reviewed and found useful for this topic will increase in importance within your refined search results and will be marked accordingly while spam sites and sites with unrelated or useless content will be pushed down in your custom search results.
You can do your search from my respective search engine page http://www.smps.us/smps-search.html or http://www.generators.smps.us/generators-search.html.
I encourage you to give it a try and see the difference for yourself. Note, this is a work in progress. I keep testing different keywords and algorithms to provide you with the most relevant search results. All comments are welcomed. To subscribe [by using any email address] click on this button:
Last revised on 2013.
July 23, 2006
Internet plagiarism
If you publish a website you may want to know if someone copied its content without your permission and is taking your work as their own. There is a nice free online tool that can help you combat Internet plagiarism: www.copyscape.com. You can enter your URL in their search box and they'll list sites that have sentences and phrases identical to yours. You'll even see the duplicated text highlighted.
When I run their search for my site among the results was a British company named Powerstax. Their Power Glossary page contained a number of definitions (such as Isolating power supply, Linear power supply, Off-line power supply, SMPS) from my copyrighted page http://www.smps.us/smps-glossary.html.
I sent a complaint to their webmaster and to other individuals whose email addresses were listed, but no one responded.
Note that definition of power electronics term on my page generally differ from those you may find elsewhere. I put up this web page because I felt the definitions given in textbooks and other sites are often inaccurate or even misleading. For example, the term Isolation is often defined as absence of current path between two circuits. In reality, it is only absence of DC current pass- as we know many isolated circuits still allow some capacitive AC current.
I was curious if the rest of the terms on Powerstax glossary page are unique. So, I run Copyscape search for their page. Guess what- the search returned glossaries of several other power supply sites. Of course, when it comes to these sites I can't know for sure who copied whom. I do know this when it comes to my site though.
When I run their search for my site among the results was a British company named Powerstax. Their Power Glossary page contained a number of definitions (such as Isolating power supply, Linear power supply, Off-line power supply, SMPS) from my copyrighted page http://www.smps.us/smps-glossary.html.
I sent a complaint to their webmaster and to other individuals whose email addresses were listed, but no one responded.
Note that definition of power electronics term on my page generally differ from those you may find elsewhere. I put up this web page because I felt the definitions given in textbooks and other sites are often inaccurate or even misleading. For example, the term Isolation is often defined as absence of current path between two circuits. In reality, it is only absence of DC current pass- as we know many isolated circuits still allow some capacitive AC current.
I was curious if the rest of the terms on Powerstax glossary page are unique. So, I run Copyscape search for their page. Guess what- the search returned glossaries of several other power supply sites. Of course, when it comes to these sites I can't know for sure who copied whom. I do know this when it comes to my site though.
July 6, 2006
RoHS overview
This year and the coming years will be challenging for electronic industry. As the July 1 RoHS deadline has come into force, no new equipment sold in EU may contain certain levels of six toxic metals: lead (Pb), mercury (Hg), hexavalent chromium (Cr (VI)), cadmium (Cd), polybrominated biphenyls (PBBs), and polybrominated diphenyl ethers (PBDEs).
Of course it is a noble idea to make electronics environmental friendlier and its recycling easier and safer. However in reality it will take years until we see all consequences of implementation of RoHS (The Restriction of Hazardous Substances) Directive. It is worth noting that the EPA report on Solders in Electronics: A Life-Cycle Assessment (August 2005) suggests that the lead-free solder replacements will have a higher environmental impact than tin lead solder in a number of areas including global warming, ozone depletion and water quality.
I also wonder what will happen with all existing non-RoHS part inventory. I guess some of them will wind up in the landfill. Others (as my boss suggested) may return to the open market through third world countries as counterfeit RoHS-compliant parts. Indeed, many manufacturers do not change part numbers and marking when they make the transition to RoHS products. For such parts, the only way to determine whether it is really RoHS-compliant is to compare its date code to the manufacturer's conversion date- something you can't do for small package sizes with no date code marking on the part itself.
The biggest challenge of course is switching to lead free solder. The main issues with lead-free allows are:
Of course it is a noble idea to make electronics environmental friendlier and its recycling easier and safer. However in reality it will take years until we see all consequences of implementation of RoHS (The Restriction of Hazardous Substances) Directive. It is worth noting that the EPA report on Solders in Electronics: A Life-Cycle Assessment (August 2005) suggests that the lead-free solder replacements will have a higher environmental impact than tin lead solder in a number of areas including global warming, ozone depletion and water quality.
I also wonder what will happen with all existing non-RoHS part inventory. I guess some of them will wind up in the landfill. Others (as my boss suggested) may return to the open market through third world countries as counterfeit RoHS-compliant parts. Indeed, many manufacturers do not change part numbers and marking when they make the transition to RoHS products. For such parts, the only way to determine whether it is really RoHS-compliant is to compare its date code to the manufacturer's conversion date- something you can't do for small package sizes with no date code marking on the part itself.
The biggest challenge of course is switching to lead free solder. The main issues with lead-free allows are:
- Tin-lead alloy has melting point of 361 F (183 C). The typical alternative alloys have melting point higher by at least 63 F (17 C). The higher temperature could damage PCBs and other components, which requires changing in the manufacturing process and materials.
- In alternative alloys, liquid solder may not attach itself to a surface as good as tin lead allow (poor "wetting")
- Possibility of "tin whiskers" (effect of growing tiny metal "hairs")
- Nobody but nobody knows long-term reliability effect of new solder
Fortunately, RoHS directive has exceptions for a number of critical categories that cannot afford any risk, such as aviation and military equipment, most medical devices, and large-scale industrial tools. Server, network and telecommunication infrastructure equipment can continue using lead in solder until 2010 and still be RoHS-compliant (so called RoHS-5 or "lead exempt"). The rest of equipment, particularly general purpose power supplies with a voltage rating below 1000 VAC / 1500 VDC not falling into the above categories has to comply.
So, what does all this mean for the electronic industry?
I guess until the dust settles we may frequently see: delayed shipments as manufacturers struggle to weed out non-compliant parts and change manufacturing process, worse financial reports, unpredictable quality issues especially with manufacturers who do not have advanced product screening system (such as HASS) in place.
Well, whatever it takes to satisfy European lawmakers (-:
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