Tuesday, 3 September 2013

Why you need to ask the frequency of LED lights

In old fluorescent lighting you just about see the flicker, although very fast, eg if you turn your head quickly round the room you could see the flashes of light like a very fast strobe. People working in those rooms didn't like this lighting effect and seemed to have higher rates of headaches, particularly if there was no daylight. ‘High Frequency’ fluorescent lights are the solution. they do flicker, but this flicker is so fast that you won't notice it (sometimes the flicker rate is up to 100,000 times per second!). Our modern T5 lights and our LED lighting is like this. But did you know that many LED bulbs and light-fittings still appear on the market with the internal 'drivers' not creating high-frequency lighting. They are very basic 'low frequency' a little like the old fluorescent lights. While it's possible for us to check the frequency using an oscilloscope, it's also possible to ask the LED sales company you're talking to. If they don't know the answer or won't tell you how their products perform, it might be safest to move on to a lighting company who will tell you this important information. After all, you can view one sample in a well-lit room and all seems fine, but if you convert a whole room to the new LED lighting you could be very aware of the eerie unnatural lighting-effect you've created. Note: the 'frequency' of the light coming from the LEDs is created by the internal electronics in the LED light 'driver'. It is not the same thing as seeing a spec of the 'mains electrical' frequency the light is designed to be connected to, so if the sales company says something like '240v 60hz or hertz' that doesn't tell you about the frequency of light the LEDs will be giving, just the type of mains electrical power the driver is designed to be connected to.

1 comment:

  1. I never really understood the effect that different frequencies could have! I never even thought it was that important, but now I understand that higher frequency bulbs appear to flicker less! I think this will also help a lot with choosing a good company that tells me about the frequency! Thank you so much for this help!



These are just my tips based on experience as a lighting enthusiast surveying sites and speccing energy-saving lighting in hundreds of buildings over ten years, and I know other people will have had different experiences (maybe different products and technologies too) so please feel free to share your own experiences here.