14-05-2016, 11:37 AM
I agree that LEDs are finally coming of age.
We have some fittings at work which were put in about 3-4 years back, and they are terrible. Just awful. But the new panels are impressive. Once my stocks of T5 tubes start to run low, I plan to fit several in my cellar (where head-height is a serious problem) - the 300mm wide variety should fit nicely between the joists and give a nice, diffuse spread of light. Of all the problems of a low ceiling, lighting is perhaps one of the harder ones to overcome (perhaps surprisingly).
The early units had 2 problems - far too blue, and unreliable electronics. The former seems to be better - although I wonder if the yellow phosphor will gradually lose output, just like it does in CRTs and VFDs, resulting in a blue shift over time. But the great unknown with any fitting - irrespective of manufacturer or price - is the quality of the electronics. I suspect the LED will outlast the driver in most cases. Similar, of course, to CFLs and many HF ballasts...
A related issue is the drive strategy. A HF buck converter supplying a constant DC current is obviously the way to do it (and I assume these are/will be available with 1-10V dimming, like HF ballasts?). But many simply use capacitor-dropper supplies from the mains, so flicker at 50 or 100Hz. Many people are sensitive to flicker, though they might not realise, and I wonder if some of the (usually irrational) arguments against LED lighting is because of that.
Of course, switched-mode power supplies can cause interference, but there's so much of that around these days that I doubt that LED lighting will make a huge impact to most of us who live in built up areas. Though if you've bought an isolated place in the wilds for some serious DXing, that might be different...
I suspect that white using RGB LEDs might be a premium option for the future. Obviously, colour-changing fittings exist, but RGB should give a better CRI than B+Y phosphor.
In TV, RGB LEDs are now commonplace. They result in a massive saving in energy costs (not just in consumption, but also shifting the heat elsewhere), but capitol costs are still very high. They usually come with DMX control, but 0-10V is also common. Of course, LED backlights in LCD panels are ubiquitous today - though quite a bit of work is needed to ensure a good spectral output. My cheap LCD in the workshop has poor reds compared to my expensive Dell, or the earlier CFL version of the same monitor that I have on my desk at work. Against that, the CFL version takes about a minute to reach full brightness, and I wonder how long the tubes will last, given that recently I had to put the brightness level up by about 20% to reach my preferred level (sad, I know, but I use a Philips PM5639 colour analyser to line up my monitors and TV sets!).
CFLs - like plasma TVs - were only ever a stop-gap. They served a purpose, and the handful that we have here are fine for what they do.
We have some fittings at work which were put in about 3-4 years back, and they are terrible. Just awful. But the new panels are impressive. Once my stocks of T5 tubes start to run low, I plan to fit several in my cellar (where head-height is a serious problem) - the 300mm wide variety should fit nicely between the joists and give a nice, diffuse spread of light. Of all the problems of a low ceiling, lighting is perhaps one of the harder ones to overcome (perhaps surprisingly).
The early units had 2 problems - far too blue, and unreliable electronics. The former seems to be better - although I wonder if the yellow phosphor will gradually lose output, just like it does in CRTs and VFDs, resulting in a blue shift over time. But the great unknown with any fitting - irrespective of manufacturer or price - is the quality of the electronics. I suspect the LED will outlast the driver in most cases. Similar, of course, to CFLs and many HF ballasts...
A related issue is the drive strategy. A HF buck converter supplying a constant DC current is obviously the way to do it (and I assume these are/will be available with 1-10V dimming, like HF ballasts?). But many simply use capacitor-dropper supplies from the mains, so flicker at 50 or 100Hz. Many people are sensitive to flicker, though they might not realise, and I wonder if some of the (usually irrational) arguments against LED lighting is because of that.
Of course, switched-mode power supplies can cause interference, but there's so much of that around these days that I doubt that LED lighting will make a huge impact to most of us who live in built up areas. Though if you've bought an isolated place in the wilds for some serious DXing, that might be different...
I suspect that white using RGB LEDs might be a premium option for the future. Obviously, colour-changing fittings exist, but RGB should give a better CRI than B+Y phosphor.
In TV, RGB LEDs are now commonplace. They result in a massive saving in energy costs (not just in consumption, but also shifting the heat elsewhere), but capitol costs are still very high. They usually come with DMX control, but 0-10V is also common. Of course, LED backlights in LCD panels are ubiquitous today - though quite a bit of work is needed to ensure a good spectral output. My cheap LCD in the workshop has poor reds compared to my expensive Dell, or the earlier CFL version of the same monitor that I have on my desk at work. Against that, the CFL version takes about a minute to reach full brightness, and I wonder how long the tubes will last, given that recently I had to put the brightness level up by about 20% to reach my preferred level (sad, I know, but I use a Philips PM5639 colour analyser to line up my monitors and TV sets!).
CFLs - like plasma TVs - were only ever a stop-gap. They served a purpose, and the handful that we have here are fine for what they do.
