New Technology sorts out: Why is flickering LED? – New Technology

Cheap electronics can lights to flicker.

Researchers in Lund warns invisible flicker in poorly constructed lamps. The reported Dagens Nyheter the weekend, a novelty that attracted great attention. But what’s the bad electronics design that causes the problems? New technologies pose five questions to Peter Bennich, lighting expert on Energy Agency.

Why flickering LED?

– light emitting diodes, are semiconductor chips that needs DC power to emit light. The lamp socket is why electronics that convert 50 Hz AC power from the wall outlet into direct current.

– The simplest and cheapest solution is a so- called diode bridge consisting of four diodes. Two of diodes passes the alternating current when it goes in one direction, and the other two diodes transmits power when it goes in the other direction. The result is a DC current with humps on the current curve. Humps smoothed by a capacitor, but the DC current is still ripple. It’s the ripple of 100 Hz receiving pilot lamp to flicker, says Peter Bennich.

Which LEDs has such diode bridges?

– Led Advent candlesticks often use solution because it is simple, inexpensive and so compact that it fits in the small shelf. When the diode bridges are used more lights, it’s probably about to save on the cost, says Peter Bennich.

Flickers all LEDs ?

– No. In our tests, we see LEDs that do not flicker at all, even cheap lamps. There are known techniques for converting alternating current into a smooth direct current so that the light does not flicker. But it is more bulky and cost a little more than diode bridges, says Peter Bennich.

How to do as a consumer if you want a flicker bulb?

– If you’re concerned, I think you should ask a dealer. You can also test yourself by keeping mobile camera near the source. If it is visible vertical stripes in the image so it points to the lamp flickers.

EU Ecodesign require the LEDs power consumption, light quality and labeling. There is no requirement flicker?

– No, do not do it, whether in the EU or elsewhere in the world. But Sweden has taken up the issue in the past and will do so again. One possibility is to do as Energy Star (US labeling for particularly energy-efficient products), namely to inform about the flicker frequency, flicker-index so that consumers can make an active choice, says Peter Bennich.

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