Joined
Oct 27, 2019
Location
Fayetteville NC
Hello all,

I have LED tape that is functioning and programable but the blue and white colors are significantly dimmer than the red or green or any color mixing options. I have tried switching decoders and switching the leads on the wiring but still the blue and white are dim. Any suggestions as to how to fix or why this is the case?
 

DrewE

Well-Known Member
Joined
Mar 18, 2019
Location
Vermont
It sounds as though those LEDs themselves are dimmer than the others for some reason. It may well be the specific LED chips that they chose to use for the tape, and in that case there's not much you can do about it other than mixing in less red and green.

One thing to verify is that the power supply voltage is correct and not sagging. The forward voltage of LEDs (the voltage they operate at) bears a direct relation to the color they emit, and blue ones have a higher voltage than red or green ones because blue photons are higher energy than red or green photons. White LEDs are actually blue LEDs with a phosphor added that absorbs some of the blue light and emits yellowish light; that and the remaining blue mix to produce something resembling white light. LEDs themselves are inherently monochromatic (or, at least, very nearly monochromatic). All that being said, if the LED tape uses resistors for current limiting, a sagging power supply would affect the blue (and white) LEDs more than the red or green ones.
 

ship

Senior Team Emeritus
Premium Member
Joined
Mar 29, 2003
Location
Illinois
Blue and White also for some (defined somewhere else I am sure) reason require more power to drive and or more amperage in driving. Blue and probably White are also more problematic in general.

Advice as above. Also check your connections in inspection to ensure no resistance due to a bad jumper or cold solder. Too long of a feed could be a thing in perhaps back feeding the circuit from the reverse end. Ever so short in calculations could be enough to voltage drop a color. Perhaps see what increasing the wire gauge of the jumper - especially the long one to the LED's might do otherwise.

This all assuming the tape you have is not of different quality than expected - would think the last theorys to work with first. Most LED tape is quality in general at least in color output when not persay efficiency or overall output in differences - more about color matching "binning" between lots of them in matching up than output problems with one or two colors - pointing to connections somewhere in pins 4&5 as it were if normally wired.
 
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