Curious LED question

#12

Joined Nov 30, 2010
18,224
Red light plus green light appears to be yellow. Switch them fast enough and persistence of vision will make them both appear to be on all the time, so theoretically, you will see yellow. A very dull yellow might be interpreted as brown, but I don't think so. There is also the consideration that some very poor quality LEDs exist. Some of them are hard to tell whether it's green or yellow in the first place.
 

MrChips

Joined Oct 2, 2009
30,714
You are thinking of red and green subtractive colors.
If you mix red and green paint you get brown.
However if you add red light to green light you will get yellow.
 

ErnieM

Joined Apr 24, 2011
8,377
Last time I did this with a red & green LED it appeared as orange with both alternating on: you need the proper mix of red & green to get yellow.
 

MrChips

Joined Oct 2, 2009
30,714
Orange...yellow, close enough. Men don't know the difference!
I'm sure if you increase the current it will look more yellow.
 

shteii01

Joined Feb 19, 2010
4,644
Last time I did this with a red & green LED it appeared as orange with both alternating on: you need the proper mix of red & green to get yellow.
That is true. On our unit it was orange when I looked down when the unit was sitting on the table, so I was looking at the led sort of from the side. But when you looked straight at it, head on, then it is more yellow.
 

ian field

Joined Oct 27, 2012
6,536
You are thinking of red and green subtractive colors.
If you mix red and green paint you get brown.
However if you add red light to green light you will get yellow.
True - but if you dim it down to low current, the yellow will start to look brown.
 
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