July 23, 2006
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
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 (-: