Headlight choices

Page 3 of 3  
On Thu, 9 Sep 2004, Tim Delaney wrote:

Yes: They aren't.
DS
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hmmm,
I have been following this topic, just for educaional purposes and I have a couple of thoughts.
1) Based on my research, these HID kits which allow you to retrofit a High Intensity Discharge bulb into an existing fixture are NOT Approved for on road use and are junk as stated by Daniel and Arif.
2) Daniel knows a lot about headlights, but isn't paying close attention to this group, as if he did he would know that Tiger is the single most helpful individual here to many of us, which doesn't mean he is always right (of course).
3) Most of this discussion is worthless to most of us as it is in some kind of headlight geek code, so as to make it impossible for laymen to understand. Although I think the laymens description that Arif gave was very informative for me.
4) Calling people names doesn't make you right, it only makes you look like a jerk.
Marty
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 11 Sep 2004, Martin Joseph wrote:

OK, maybe he's an expert on every aspect of Mercedes cars *except* the lighting. He can take the rest of the car; I'll take the lighting.

What part of the below is in "headlight geek code"?
Halogen headlamps and HID headlamps require very different optics to produce a safe and effective -- not to mention legal -- beam pattern. How come? Because of the very different characteristics of the two kinds of light source.
A halogen bulb has a cylindrical light source -- the glowing filament. The space immediately surrounding the cylinder of light is completely dark, and so the sharpest contrast between bright and dark is along the edges of the cylinder of light. The ends of the filament cylinder fade from bright to dark.
An HID bulb has a crescent-shaped light source -- the arc. It's crescent-shaped because as it passes through the space between the two electrodes, its heat causes it to try to rise. The space immediately surrounding the crescent of light glows in layers...the closer to the crescent of light, the brighter the glow. The ends of the arc crescent are the brightest points, and immediately beyond these points is completely dark, so the sharpest contrast between bright and dark is at the ends of the crescent of light.
When designing the optics (lens and/or reflector) for a lamp, the characteristics of the light source are *the* driving factor around which everything else must be engineered. If you go and change the light source, you've done the equivalent of putting on somebody else's eyeglasses -- they may fit on your face OK, but you won't see properly.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks Daniel! Thats very clear...
Marty
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 12 Sep 2004, Martin Joseph wrote:

You are welcome.
DS
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.