| Electronics > Beginners |
| Lab lights, how much are you happy with lights in your lab |
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| 3roomlab:
--- Quote from: floobydust on May 06, 2019, 11:38:13 pm ---CRI is just a number, a bunch of math that can be fudged. It is not great with spikey (LED) spectrum. High-CRI does not work well with film photography but the number says it should. The DIY fixture is two sets of three LED strips with different colours (ice blue, warm white, daylight pure white), each with a PWM dimmer. Not very bright, and better for background lighting, not task lighting. --- End quote --- I remember reading that the standards body has defined a new color standard to replace the CRI, the TM-30-15. TM-30-15 depends on a 99 color spots, CRI is up to 16. manufacturers refused to use the new rating I think it is because with CRI, it is easy to "cheat" buyers. the new rating will also cause many of the existing products to fall into mediocre low range. this in turn can be seen in the actual pdf at say digikey, I have seen not one using TM-30-15 there are only so few pdf that will show you actual spectrum, and there are always the same few manufacturers that show intentional vague data of the spectrum (thick unrealistic plots) |
| David Hess:
--- Quote from: Ian.M on May 03, 2019, 11:14:27 pm ---Long tube 'daylight' fluorescents and lots of them is the way to go for general lab lighting. The length of the tube reduces sharp shadows laterally, and if you have several tubes well spaced out side by side, you can also minimize front to back shadows. --- End quote --- I agree; I much prefer linear fluorescent tubes to any other form of lighting for the reasons you give. In addition, desk mount fixtures which hold two 2 foot tubes for close in lighting are available and tubes are available with whatever color rendering you prefer. I find that a mixture of cool and warm tubes works best but there are lots of options. Power line EMI has become so strong that I do not notice any addition from electronic ballasts for linear fluorescent tubes. The designs I have inspected use soft switching topologies like resonate Royer converters so maybe that is why. |
| HB9EVI:
for years I used a lamp with G23 socket and fluorescent bulb what often required to be turned off when it interfered too much with the scope; then I found led bulbs matching for the socket - what a surprise: EMI was even worse than with the fluorescence bulb. just recently I decommissioned it and got me a led lamp with integrated magnifying glass - which is free of EMI and does a good light (day light 6600K) |
| schmitt trigger:
Back in the days, when all ballasts were magnetic, the thumb rule was to always use a dual-tube ballasts. The reason was that fluorescent tubes flickered tremendously, which could strain your eyes. On a dual-tube ballast, one of the tube currents was phase sifted with the aid of series caps, such that as one tube was going down in brightness, the other was reaching peak luminosity. This was eliminated with high frequency ballasts in the 90s. However the newer cheap designs do away with most if not all the bulk powerline filtering, and therefore the high frequency carrier is modulated with powerline frequencies. |
| akowalczyk:
Cheap LED strips on Ebay can work great, they aren't a point source so you have less shadows. Figuring out a fixture to hold them can be a bit of a problem though, my roomate and I came up with a PVC frame held up by thick magnet wire and wall hooks. Only fell down a few times...and fortunately never when we were soldering |
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