Physics: Principles and ProblemsChapter 29:
Solid-State ElectronicsProblem of the Week <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/ch29_title.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (1.0K)</a>]]> | Haze
When dust, smoke, pollen, or tiny droplets of water float in
the air, the sky becomes hazy. Over the last few hundred years,
the skies around the globe have become much more hazy due to
industrial smoke, car pollution, and forest burning. Because
haze scatters sunlight back into space, there might be a slight
cooling effect in the northern hemisphere that would alter weather
patterns. On hazy days, people with light skin can receive a
sunburn even when in the shade. In some regions, haze can be
so thick that shadows are faint or nonexistent. | LED
haze detectors costs less than $20 and can be put together in
under an hour.  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/lilGuy.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]>
| Sun
Photometer
A Sun Photometer is a device to measure the intensity of light
from the sun. Because haze reduces the intensity through scattering,
the photometer also measures haze. You have probably heard of
a Light Emitting Diode, a semiconducting device that generates
light when a current passes through it. This process can be
reversed: light falling on a LED produces a small current that
can be detected. A device that makes use of a LED to measure
haze is quite simple to construct, and that is the Problem of
the Week.
 <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/ch29_haze_o_meter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (11.0K)</a>]]>
Haze
Photometer
|  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/POWproblem1.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | At
the web-based Haze Sun Photometer Atmosphere Network, HAZE-SPAN,
amateur scientists worldwide share their atmospheric haze data.
Most members use the simple LED haze photometer. Instruction
for making this device can be found at their site, http://www.concord.org/haze/.
To gain first hand experience with semiconducting devices, build
a LED haze detector. |  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/gutter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/gutter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/gutter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/gutter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/gutter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> |
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