Electrical Conductivity and Resistivity

I guess “conductivity” and “resistivity” are terms relatively simple to explain to the general public. Conductive materials conduct electrical currents easily, and resistive materials resist electrical currents. So what should an engineer know about these terms that the general public does not generally know? By knowing how they are defined, and knowing the difference between resistivity and conductivity, and resistance and conductance.

No, this is not about "Resistance: Fall of Man" game (image taken from Best Game Wallpapers).

Metal whiskering

Do you know that not only mice and felines grow whiskers? Metals do too! Surprise surprise! To system and electronic engineers however this is an unpleasant surprise, a nightmare that they wish never will happen in their products. This phenomenon gain so much attention that high tech companies such as Lockheed Martin and NASA are still trying to understand it.

The removal of lead from solders increases the chances of tin whisker occurring. The phenomenon of whiskering had caused multimillion havocs, including the false alarm of Millstone nuclear plant, Swatch watches recall and the lost of Galaxy IV satellite (image taken from The Guardian).

Resin Identification Code

If you were to flip over most everyday items made of polymer, especially those which are disposable, you would have noticed the triangular sign with a number within and maybe some alphabets below. This is the Resin Identification Code, and unless you were working with a disposable consumer item and your company is committed to label their product accordingly, you may not have given it  a second's thought.

Image taken from Flickr (by holeymoon)

In order to address the recyclers' rising need for a clear indication of polymer used, Society of Plastics Industry, Inc (SPI) developed and introduced the identification code in 1988. This code is usually found in packaging and containers since these are the main targets of municipal recycling programs, seeing that they are one of common items encountered within residential waste.

The code is used solely to identify the plastic resin in a manufactured item. In fact, the triangular label with 3 twisting arrows along with the number within are commonly misinterpreted. The number within is an arbitrarily chosen number to represent the target plastics, and has nothing to do with ease of recycling. A higher number does not mean that the plastics is harder to recycle.

Folding Plug

Ever thought of the fact that however portable and sleek your laptop or latest gadget is, the huge rectangular plug with its 3 bronze pins sticking out totally diminishes the definition of "sleek"? No matter how innovation is done on every part of an electronic device, the plug is the one with almost nonexistent change as far back as anyone could recall.

Folding Plug can, as its name suggests, be folded and carried with greater mobility (image taken from The Guardian).