The There Are No Stupid Questions Thread

some where i saw a blf host diy. I thought it was banggood but can’t seem to find it now it my also have been a sofrin host does anyone know what i’m referring too. thanks

What’s the trick to soldering emitter leads to the emitter board?

I did my first three driver swaps and soldered the leads to the original emitter boards (to aluminium, one copper) without a problem, but now that I’m trying to put a new emitter in my L2 I just can’t melt the solder on the pads.

I have a 30W temperature controlled soldering iron. Do I need more power?

It is about three things, more of each is better:
*power (but 30W with a quality tip is enough for most emitter board joints)
*contact surface (the pointy end of a small tip is not going to do it, a bit further down the tip where it widens is much better, or use a flat-end tip)
*a clean tip loaded with some fresh solder for a good thermal bridge (oxide layers are excellent thermal insulators)

… and one more thing:
I don’t know if you are trying to solder to an already mounted MCPCB - if yes, it does what it is expected to do - leading the heat away. Lift the MCPCB a bit. If there are screws - loosen them before.

Thanks djozz and Flashy Mike.

I think the tip might be the issue - it’s a small conical tip and there isn’t enough room to use the side, and it is looking a bit oxidised.

I’ll try some tip tinner and working with a blob of solder on the end. If I still can’t get it to work I might get a cheap 40W it on and flatten the tip.

How are babies made?

Can a HF 9-led 3-AAA giveaway light be modified in any useful way economically?

I got one just like that!

I bought it at the Darth Mall.

What is the impact of a reflector which is not 100% spotless?

To tweak the beam of my C8 i have sanded down the gasket until it was paper-thin, which improved the beam but it was still not a laser beam, it diverges.
So i filed down the reflector quite a bit, i dont have the guts to go any further at the moment.
Filing and sanding caused a dirty reflector. I have messed up 1 reflector earlier and now i know it is a p.i.t.a. to get it clean.

Got it quite clean with soap, running water and a hairdryer :wink: but it still shows minor stains due to dried water, which annoys me, do i have to, other then cosmetics?

I believe you mean, “How is babby formed?”.

And its corollary question, “How girl get pragnent?”.

The influence of some dust specs can not even be measured, but stains really do influence the throw somewhat, but nothing that can be seen by eye.

About beam divergence: a led in a reflector can not be seen as a point source, led dies have a certain size, the hotspot of the beam is in fact a (twisted) image of the led die. With the led as source, the reflector as optic, and the hotspot as image, the normal lens formula sort of applies in which the distance from optic-to-hotspot divided by the distance from led-to-optic determines the magnification of the led die, the size of the hotspot.

In short: because a led is not a point source, the beam in even a perfect reflector will always diverge.

Mostly , in the old fashioned way...

Thank you Jos, very helpful!

I’ve had pretty good luck before rinsing a reflector with distilled water and using a can a air to help blow out the particles, then rinse with isopropyl (rubbing) alcohol and blow it out again with the air. Using distilled water and the alcohol didn’t leave water mineral marks.

Thank you Robert, i was thinking the same, have to buy some compressed air, or even better a compressor :wink:

why dont make 3V version xhp70.2 :frowning:

I’ve read there often is some oil in compressed air which is not good for reflectors. I use this tool with good success:
https://www.amazon.de/Giottos-GTAA1900-Rocket-air-Blower-schwarz/dp/B00017LSPI

One possible reason: lower voltage (all LEDs parallel) means higher current for same output which results in more resistance losses in cables, contacts, PCB traces et al.

Thanks Flashy Mike, just ordered one from BG, will try out soon!

okay, then Why CFT-90 not running on 12V led :stuck_out_tongue: