Good Job!! Thank you do that :THUMBS-UP:
Hi,
Great post.
Awesome post,artfully done.
I`ll be back.
Superbly Done!!
Thank You Thank You Thank You
This is truly amazing and extensive! You could use this to create a course curriculum for a 2-day seminar. 
Here’s a couple missing LED V/I graphs for the OP
Here’s corrected version of the ANSI Cree binning chart with the CCT and BBL lines in their right places.
D-c-fix link might be in order: D-c-fix diffusion film
Thermal paste vs. graphite thermal pad:“https://budgetlightforum.com/t/-/56535”
hi
i have a basic question
what is a DTP mcpcb and diffrences with no DTP board?
We use basically three types of MCPCB (Metal Core Printed Circuit Board)
The difference between DTP (Direct Thermal Pad) vs Non-DTP is mostly due to how the centre solder pad of the board is connected to the rest of the MCPCB.
Most of the LEDs we use have three soldered connections, a positive, negative and thermal pad.
They are made roughly as illustrated below:
The first aluminium board has an insulating layer (yellow) between the central heat pad solder point and the base of the MCPCB, this is bad for conducting heat away from the LED which is very important in higher current applications.
In the second diagram you can see how the base copper is not obstructed by an insulating layer at the central thermal pad connection and so the LED thermal pad is soldered directly to the whole of the base, very good for wicking heat away from the LED.
In the third version there is a very thin layer (microns) of aluminium oxide or ceramic type material insulating the thermal pad from the rest of the board but this version is also extremely good at removing heat from the LED as the layer is so thin.
This type of board can also have an added advantage because the thermal pad is electrically isolated from the rest of the board which some setups require.
Those 3030 20mm boards in last picture are copper DTP, these are Alu-oxide:
https://led4power.com/product-category/mcpcbs/mosled-extreme/
You can use picture of IR LEDs as example of mcpcb with LED installed:
https://led4power.com/product-category/infrared-leds/
The alu board weighs less and is easier to file to size as well.
It’s not the best for every use but overall my favourite kind of MCPCB.
thank you
i have a normal non-DTP copper core mcpcb.because in my region there isn’t DTP mcpcb and i cant order that!
so can i scratch center pad of non-DTP mcpcb to reach copper core an then solder LED’s center pad directly to that scratched surface for maximum heat transfer?is that a right and effective way?
CRX - I see that type 1 mentions alu substrate. This may make people think that all copper PCBs are DTP. I suggest to amend that for clarity.
yoosefheidari - yes. It’s cumbersome but doable and working.
Good point. The amount of times I have been pleasantly surprised to see a copper MCPCB only to then be disappointed by a multimeter… :person_facepalming:
What is your intended setup? Some say that Non-DTP MCPCBs are fine up to 3A.
Take a look at this thread. Copper MCPCB Mods
And these. 6x 20mm XML-ledboard comparison
Just documinting my DIY direct thermal path
Some of us used to even drill a hole through the thermal pad of aluminium MCPCBs and install a piece of copper to make it sorta DTP, the good old days 
thank you so much
these threads help me so much
about my setup i want to drive a xhp70.2 at between 5-10 ampere; so i need a good heat transer solution
hi again
i bought a xhp70.2 for my diy flashlight
i have a question.i run the led at 1 watt and pcb temp was normal about 25 degree(room temp)but led surface(dome)temperature was about 45 degree.is that ok?
Absolutely perfect.
You will never have problems unless you go around 100 degrees Celsius.
thank you
i use a plano-convex for my flash light.lense’s diameter is 7.6 milimeter.
there is a problem with this lense.at 10 meter distance on a wall light’s diameter is about 70cm.but that is to much and i want it about 7-8 cm at this distance.which lense should i use for this goal?
I think there are 4 factors that affect spot size:
- Whether the lens if fully focused. Some lights purposefully don’t allow you to fully focus their lenses which makes the spot larger than it could be. Focusing better would make a tighter and more intense spot.
- F number. This is a parameter related to the exact shape of the lens. Lenses with smaller F number are stronger, if you used them for magnification - they would magnify more. F number affects distance from the LED at which the lens is in focus. A stronger lens will achieve focus closer to the LED. Now…please note that light that doesn’t hit the lens is wasted. Stronger lenses collect more light so they are more efficient. This efficiency makes the spot larger without making it less intense. Up to a point, very strong lenses tend to be less precise which hurts throw. You really need to test to tell whether you’ve got a good one. So…using a weaker lens would reduce your spot size. But it wouldn’t make it brighter. And I suppose that making it brighter is the whole point.
- Lens diameter. Larger lenses collimate better. This is directly proportional to lens frontal area. If you got a lens that has the exact shape of your current one but has diameter of 76 mm, the spot would be 10 times smaller in diameter (7 cm), 100 times smaller in area, 100 times more intense.
- LED used. LED die size is directly proportional to spot size. Using a smaller LED would make it produce a smaller spot. So changing from XP-L HI (3.55 mm²) to White Flat (1.069 mm²) would reduce spot area 3.32 times and spot diameter by 45%. If you use XP-L HI, going with 0.25 mm² Osram Synios would reduce your spot size to 19 cm. Spot area is proportional to die area. Spot intensity is proportional to die luminosity which is unrelated to die size - and changing LED may make your beam more intense but it can make it less intense as well.