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This is the study using EVOs to which Samsung refers. But it's lettuce :|:| Effects of White LED Lighting with Specific Shorter Blue and/or Green Wavelength on the Growth and Quality of Two Lettuce Cultivars in a Vertical Farming System From conclusion, "At the same electrical power, the new...

I am very interested in learning more! Are both the 3000k and 5000k Samsung LM301H EVO diodes? What type of diodes do you use for 660nm and 720nm? Can you list the diode mix, i.e. quantity of each diode on the board?

Wow! Thanks for sharing all this knowledge Prawn Connery!

To clarify, here I meant the series replaced by parallel strings, like this:

On this light the EE said that the power to the series would be uneven. And that the diode intensity in Series 2 might be different from that on Series 7. And this was because all the series draw off of that one green-tinted positive pad. Could this be a thing? I don't know much about...

I'm going to ask, thanks!

I have a discussion going with an EE about the PCB design of this light. He says the design is inherently poor because it is using unregulated series of diodes. He claims that, because each series is unregulated, the diodes will be difference light intensity. He introduced the idea of 25% loss...

Is it a mix of both? I think I've noted 13 series circuits here, all feeding from the one big positive pad (see green overlay). If this is the case, how does the power get equally distributed to each of the 13 series circuits? Please be kind :) I have a limited idea of electronics. I believe...

https://planthardiness.ars.usda.gov/ Here's a closeup of Massachusetts.

These are incredible! I'm blown away these are here in Massachusetts, especially with the wet summer. You wrote "1:3 peroxide spray every couple of days" for problems. I was wondering if you used anything else?

40% off. Buy two? 30% off this one.

I also came across this technical note (https://www.upowertek.com/what-is-pwm-dimming/) about Fake PWM Dimming, which I think is what I'm getting confused about. Would this still be constant current?

How does dimming work on an LED panel? Does the power supply voltage drop like analog incandescents? Or does the supply get chopped up like I've read with PWM? I'm interested in constant current output but PWM adjusted duty cycle coming out of a power driver. Is this even such a thing and who...

What are you talking about? Where did this come from? :confused: Very funny.

Just to clarify. The mint white diodes are a specialty LED, not a complete spectrum. Here's a graph where you can see the Samsung EVO mint white diode in blue and the EVO 5000K in black. The mint white spectrum is different, but it is not really complete. I think you were referring to the...

Thank you!! This is an amazing insight into how modern LED lights are constructed! I'm really intrigued by the large copper traces. I disassembled a $50 sale 100w light and took a photo of the aluminum PC board. Now I can see how almost the entire board is covered with wide copper traces...

Thank you very much. I didn't know the entire board was aluminum! And, after adjusting the contrast, i can easily see the traces.

I have a technical question about thermal management with mid-power LED diodes like Samsung LM301H. Do you use thermal vias on the PC board anymore? Either under the LED diode footprint or even around the footprint? I was reading about this on a ten year old application note from Cree called...

#3 has a good deal of red, so that's something to consider. Might be more suited for flower? 2. about 5% deep red, and 1.5% far red 3. about 15% deep red, and 5% far red

$139.99 with $30 coupon. I have no experience with this light. But it will cover a 4x4. Spectrum is adjustable, too, from the looks of it. https://www.amazon.com/SONLIPO-SPF2000-Coverage-Samsung-Spectrum/dp/B09PV87W9H/