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| Cheapest way to check if a UVC bulb is as advertised? |
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| pipe2null:
The topic says it all. There probably is no cheap way to do it if you don't have the right equipment, but I don't know since I've never had reason to measure light/UV emissions before. I ordered a small variety of different UVC bulbs for pandemic purposes. I figure replacement UVC bulbs for use in products from larger companies are probably as advertised, at least the official replacement parts. But then there are some LED UVC lights, with convenient household light bulb screw connectors, that claim to emit 254nm UVC at various power output. At first I thought it was total BS, but apparently UVC LEDs are a thing now. "Ideally", I'd like to know what wavelengths are actually emitting, and how much of the advertised 3.5W, 30W, 60W, 100W, etc power is actually being emitted at 254nm UVC. It would also be useful to measure the same info for replacement UVC bulbs for normal commercial products as well. Also, even if 254nm exist, also would like to verify that no lower wavelengths are emitted that produce ozone. But that's "ideally". :-DD Is there a cheap way to do this? |
| Siwastaja:
About the LEDs, UVC LED bulbs that advertise multi-watt numbers and don't cost a fortune are likely just scams, or just rated by the input power, which is meaningless. The state-of-the-art UVC LED efficiency being somewhere around 2-3% and the cost somewhere around $1000/W for output power. So they are in the same spot now as white LEDs in mid-to-late 1990's. Also, you don't want to buy 254nm UVC LEDs, because that's not the optimum wavelength. With LEDs, you have the choice for 275 or 285 nm products. |
| jpanhalt:
One can find various inorganic compounds that fluoresce when exposed to short wavelengths. Orange and green are will known and used in TLC (thin-layer chromatography) plates like this: https://www.coleparmer.com/i/kinesis-telos-aluminum-backed-tlc-plate-with-gf254-indicator-silica-200-x-200-mm-20-pk/0647587?PubID=VV&persist=True&ip=no&gclid=EAIaIQobChMIgZXynY7M6AIVm4FaBR3k5QaWEAAYAiAAEgJl7fD_BwE There might be some organic compounds too, but the inorganic compounds are more common and stable. Now,of course,there are lots of fluorescent organic compounds, but most of them, e.g., fluorescein and rhodamine, fluoresce when excited by longer wavelength light. |
| NiHaoMike:
Get an old EPROM and see how long it takes to erase. |
| pipe2null:
So, moral of the story is UVC LED products currently sold on Amazon are ALL? scams since it is not currently possible to produce them within consumer price ranges??? I was and still am skeptical of those products, but doing actual measurements confirm reality, up to the limits of your testing ability, which is my current issue. Does anyone know a good de-rating factor to use for "should probably be as advertised" UVC replacement bulbs for commercial products, the actual glass bulbs with... I think mercury? By "de-rating factor" I mean the actual power output in the germicidal range given the advertised overall power consumption of the bulb. I have one "replacement" bulb on the way that is advertised as 3.5W, but I reasonably assume that is the power requirement and not the actual emitted UVC power. I'll have the same issue with any other bulb I order. |
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