Newbie needs help (LED "Flashbang" project)

Audioguru again

Joined Oct 21, 2019
6,826
The small COB at Digikey is obsolete but they still have some in stock. It is only 7W so its heatsink will be small, but for 156W like before with the four huge COBs, you will need 22 of them.

The Cree COB is 9W so for 156W you will need 18 of them.
 

Thread Starter

Cheerful_Scumbag

Joined Nov 20, 2022
10
The small COB at Digikey is obsolete but they still have some in stock. It is only 7W so its heatsink will be small, but for 156W like before with the four huge COBs, you will need 22 of them.

The Cree COB is 9W so for 156W you will need 18 of them.
I'm confused. I wasn't trying to match the power of my cobs @djsfantasi said I should find a 12v cob instead of using the 30v bridge lux cobs I have. I don't know if any of them would be bright enough
 

Audioguru again

Joined Oct 21, 2019
6,826
The number of Watts (brightness)= voltage x current. 33.4V x 1.17A= 39W. Four of them are 39W x 4= 156W.
If you use 12V COBs then for 156W you need a current of 156W/12V= 13A.
If 12V COBs use 300mA each then each has a power of 12V x 0.3A= 3.6W. You will need 156/3.6=44 of them.

each LED cOB might need a series resistor to set its current. The LED with the resistor will need a higher voltage.
 

djsfantasi

Joined Apr 11, 2010
9,237
I'm confused. I wasn't trying to match the power of my cobs @djsfantasi said I should find a 12v cob instead of using the 30v bridge lux cobs I have. I don't know if any of them would be bright enough
Why don’t you get a smaller COB and test it to see if it’s bright enough? We can make suggestions but without metrics (which you must supply), we have no way of determining if it will satisfy you.

Plus, there are LEDs (not COB) which are made for flash units. Search for “flash leds”.
 

djsfantasi

Joined Apr 11, 2010
9,237
The small COB at Digikey is obsolete but they still have some in stock. It is only 7W so its heatsink will be small, but for 156W like before with the four huge COBs, you will need 22 of them.

The Cree COB is 9W so for 156W you will need 18 of them.
If he needs 156W. I’m not convinced that he knows.
 

Audioguru again

Joined Oct 21, 2019
6,826
Remember incandescent light bulbs for inside homes? A 60W bulb was common but a 9W LED bulb produces the same brightness.
Then 156W of LEDs is the same as 1040W of incandescent bulbs.

An incandescent light bulb cannot "flash" because it slowly lights up then much slower turns off (heating and cooling times).
 
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