Were you able to make it to Tuesday's presentation (slides here) by Bob Kottritsch, Vice President of Lynk Labs Inc.? Bob certainly presented an excellent summary of how lighting technology has evolved, starting at 70,000 BC! He then really got into the detail behind LEDs and how they themselves are evolving. However, were you convinced by the arguements for a shift to AC, rather than the typical DC, for powering LEDs?
Comments on the topic in general are also very welcome. Would you like to see more events of a similar theme, or do you have suggetions of topics you like to see covered in future seasons?
Fascinating talk. The only info I didn't catch, but was hoping to, is how to tell AC LED from DC LED products. I am not sure this is something that will be made clear on packaging.
Yes, a fascinating talk- I didn't realise how late it was!
My only concern with the proposed ac arrangement is that of using a diode bridge to power the LEDs. Because of the high threshold voltage before current is taken, there is risk of history repeating itself. Low power devices such as these do not have to meet the same regulations as high power products when it comes to harmonic currents and flat topping of the supply voltage.
The history I refer to is the effect seen in the City of London when a concentration of computers first appeared in the financial offices of banks etc. There was a fire in a substation which was found to be caused by overheating of a neutral cable. When single phase loads are collected together in a three phase system, the triplen frequencies in effect cancel out and don't flow in the neutral but with bridge rectifier single phase power supplies there are large 5th and 7th harmonics. These do add up in the neutral and became larger than the (at the time norm) of rating the neutral conductor much smaller than that of the line conductors.
With the large number of replacement LED Lights indicated by the speaker, I believe the simple AC LED light will distort the supply unless we put back in the power electronics to create a so called "active front-end" to ensure the lights take a sinusoidal current - just like the old filament lamps.
Not sure the video answered the question, unless everything with a Lynk Labs label is AC . .But I suppose the technology is not the issue, it is functionality, performance and reliability per cost that matters. And I assume we have to wait a while yet for cheap, 'warm' and dimmable, long-life BC LED light bulbs.
