Recent content by Book

This is the LED and the driver below it (for the eBay flashlight posted above): Photo I am still not sure if the LED is genuine, as I've seen the "Cree" and other details written onto the LED's surrounding white space in some youtube videos. I couldn't remove the driver from the housing (it's...

I am only using rechargeable 18650 cells. I have a pair that I've purchased from DX, and a set of 4 Nitecore ones that I got from Amazon. Both seem to power the same lights with the same amount of current (visually same lumen output). I do not use AAA ones at all. So batteries do not seem to be...

I'll give you a prime example which illustrates my point, eBay item number 321164610527 Awesome price, Great body, and possibly a genuine Cree LED. The light output sucks though. How do I fix this? Is it the driver? Poor heatsinking is out of the question, because lumen output is more or less...

I've bought several of the flashlights sold in Chinese webpages, and on eBay. They are supposed to have very good LEDs, similar to those used on high-end brand-name flashlights (eg. the XM-L T6). Now these flashlights come nowhere near their advertised lumen output. That's somewhat expected...

Hi, I'm looking to get a new quality portable flashlight. I've always shopped Chinese LED ones, but now want to step up the game a bit. I found out about this company, nitecore, and their products impressed me (certainly not very good bang for the buck though). But I really must know what other...

Besides all that, why does divergence seem to be a problem? Can't they manufacture lasers with an adjustable cap so that it makes the beam leave straight. Since when the light leave the diode it has (say) "positive" divergence (it doesn't leave straight but cone-shaped) why does the lens always...

Actually it is possible that power of the laser and the mv are directly proportional, so you only need to verify that. If it's true then it would need 2 measurements of different mw lasers to determine the factor by which those are proportional and then you can calculate power output only by...

Yeah, I would really like one that could detect higher wavelengths IR (except near IR), as those emited by hot bodies. Are they really so expensive? And when I was talking about the theoretical devie that could deetct all electromagnetic radiation, I was kind of picturing it having a monitor...

Yeah I meant that kind of test! Is it true that you should use LEDs of the exact (or at least of about the same) nm as your laser? I think this is because that is the frequency it captures the best, but then again it won't really matter, since all you do is comparing volt values. But, if you...

What about the method I said? Hasn't anyody tried it?

Do you know of any place that I could buy a camera that could detect IR visible UV light or any combination of these? For example, I'd really like a micro-camera that could detect IR (preferable of a large range). I don't want it to have a high resolution, but it has to be sensitive enough...

Yeah, ok I agree on that. But I was just wondering about divergence and why it's so hard to have a beam leaving straight. Besides, if it lands on the moon on a relatively tight dot, maybe the austronauts would be able to see it

OK these are my last questions I won't bother you anymore with the IR filter!

You say divergence will not allow this. Can't you adjust the lens is such a way that the beam leaves without diverging, or at least it creates the dot very far away? It can't be impossible.

Re: Is it a suspect/dangerous laser, how can I be Damn posts are flooding in so quickly over the hours, you talk so much! X-rays are ionising, and that's another matter, we're not talking about ionising radiation here (that means, pretty much, no shorter wavelengths than violet). And I didn't...