Free Republic
Browse · Search
News/Activism
Topics · Post Article

To: The Toad
Got bad news for you. It is likely cheap LED based lighting will have at least as much flicker as a cheap CFL.

CFL’s get some smoothing of the light output from the persistence of the phosphors used. Different phosphors have different persistence and can be chosen to produce less flicker. LEDs have no inherent persistence (at least in human terms).

The only other way to minimize the flicker is filtering on the AC to DC power supply which takes relatively expensive and bulky capacitors. When cost is the main driver they'll take short cuts on this.

51 posted on 03/28/2009 5:18:52 AM PDT by DB
[ Post Reply | Private Reply | To 44 | View Replies ]


To: DB

The typical white LED is also phosphor-based, so it has a time-smoothing effect similar to that of a fluorescent.

You can also get tri-color LEDs, which have three chips that emit primary colors and whose intensity can be balanced for a wide gamut of colors. These are more expensive per unit of light output. Since these have no phosphors, there is no time-smoothing effect.

You’ll never get entirely rid of the light pulsations, because the efficiency of an LED depends strongly on pulsing high currents through it at low duty cycles. However, the circuitry can be designed, for a price, to make the pulses high in frequency, in which case the pulsing is likely to be noticed only in the stroboscopic effects seen with rotating machinery and the like.


94 posted on 03/28/2009 8:23:23 AM PDT by Erasmus (These days, it's hard for an iconoclast to keep up his image. -- Sid W Sodnagel)
[ Post Reply | Private Reply | To 51 | View Replies ]

Free Republic
Browse · Search
News/Activism
Topics · Post Article


FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson