Re: Design of a Fan controller

JPG wrote: 
On Sun, 17 Jul 2005 14:49:53 -0400, Jerry Avins <jya@xxxxxxxx> wrote:


Scott Seidman wrote:

"kumarkk" <kumarkranthi@xxxxxxxxx> wrote in news:1121447195.918447.199180
@z14g2000cwz.googlegroups.com:



I am new to this group. I am pursuing my masters in electrical
engineering. I have opted a control systems course in which I am facing
difficulties.


Frankly, as a Master's student, you shouldn't be posting required specs and asking for an approach. You should be posting specs, telling us about what you've tried, the high points and low points of the output behaviors of the approaches you've tried, and what direction you see your next approach taking.

Unfortunately, Scott, that depends more on the school than on the student. I knew a Ph.D. in EE who believed that curving one side of the symbol for a capacitor was a matter of artistic license. 


That's an American thing - UK capacitors have straight "plates", except for
electrolytics, which have the positive plate "thickened" and a + alongside.  I
was never sure what the meaning of the curved "plate" was - maybe it was just a
cultural thing alongside valve/vacuum tube, anode/plate - reflecting parallel
development of electronics on both sides of the Atlantic up until about 1970,
since when the US has dominated and recent electronic vocabulary and symbology
has become unified.

The curved plate has exactly the opposite significance of the British thickening. It is the negative end of a polarized -- usually electrolytic -- capacitor. Because the US and British conventions differ and each convention is used in several countries, the plus sign is added. My generation rarely uses it, but we're on the way to extinction.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
.