You helped me with some of your idea'*....I thank you!

Ditto... thanks to Jim and the RLD for that.

But great write up.....
I might change my door lights to red LEDs thanks to that write up.

its possible to wire a set two sets of LEDs and put a switch so you can go from white to red if you really wanted to, Im not sure where you would put the switch though. How much do you charge to assemble them all? I couldnt find a price on your website. I'll have to remember this for a summer project

One additional note when you're dealing with expensive LEDs -- not all manufacturers agree on which leg of the LED should be the long one. I've fried a number of LEDs assuming that the long leg was the anode (positive). Make sure you check the spec sheets before wiring everything up and applying power.

-b

Just a couple of things:

enmityst: Unless you're pushing way too much voltage through your LED'*, they won't burn out if you put them in backwards--they juts won't work. This is because they are diodes that emit light when electricity passes through them (Light Emitting Diode). The reverse voltage is usually many times the forward voltage. That said, if you burn 'em out backwards, they'll stand no chance correctly installed, either!

StoopidSavant: The LM317 idea is pretty cool, but that'* gonna require about 4 other compnents as well (2 resistors and at least one cap, if not both of them). You won't have much space if you put that up with the light. Also, the equation for the typical application varies slightly based on current, which is variable with your LED based on temperature. However, I didn't run any numbers through that equation to see what magnitude difference could be returned. Personally, I'd recommentd a simple resistor, since you know what your LED draws typically. Taking that into consideration with a 5% resistor tolerance, and a peak voltage of 14 volts in your cars electric system, to be safe, you should be able to establish 3.4 volts with error allowing only 3.6 volts. And if your LED only recieved 3.3 volts due to allowing overhead, I'm sure it'll display between 8000 and 9000 MCD'* easy. Just a though.

I've also come across these different sites that you could buy LED'* already assembled in standard packages/bases, and thought it was really cool. That'* partly where I got the idea! Maybe I shoulda mentioned that. Oh well. Obviously, it'd be easier to buy many of their products than to make your own. It'* always cool to say you made it [the simple stuff] yourself, though!

-Grant

The PIV (peak inverse voltage) rating of a standard diode may well be many times larger than the forward voltage drop (say, 100V PIV vs about 0.7V forward drop for a generic 1N4002 rectifier diode), but LEDs are a lot less tolerant of error. For example, a Micro Electronics MBB31D 430nm (blue) LED has a forward voltage drop of about 3.8 to 5V. It'* PIV is 5V, not 100V like its rectifying cousins. So you could certainly waste some of these LEDs if you decided to hook two of them in series across 14V with a small current limiting resistor and accidently reverse biased them.

The difference is that in the forward bias direction, the energy you're imparting to the electrons is mostly released as light; however, in the reverse direction, you're just building up an electric field across an excessively small semiconductor barrier. When that electric field gets close to the PIV rating of the diode, electrons start jumping across the barrier with a huge amount of kinetic energy, leading to avalanche breakdown and a destroyed semiconductor junction.

-b

which did you like better in the overhead lights, the 4 LEDs or the 8'*?

I like 8 led'* overhead better than the 4, it'* a touch brighter.

And I recommend using cheaper LED'* (with reverse voltages over 10 volts). It'* not worth paying the extra money unless you're dealing with rocket science precision through an acceptable level of accuracy.