I saw some 3W GU10 LED lamps on ebay that were available in red, yellow, green and blue. I bought one of each along with some other lamps for fun.
They look good, but the yellow one is notable for being surprisingly bright and richly coloured for a yellow LED lightsource. The traditional yellow Gallium Arsenide LEDs always tend to look a bit dull and washed out. The LEDs were also notable for appearing yellow coloured when unlit leading me to guess that they might actually be a Gallium Nitride lightsource stimulating yellow phosphors. In this video I pop the lid on the yellow lamp and test the forward voltage of one of the LEDs to see which technology it uses.
They look good, but the yellow one is notable for being surprisingly bright and richly coloured for a yellow LED lightsource. The traditional yellow Gallium Arsenide LEDs always tend to look a bit dull and washed out. The LEDs were also notable for appearing yellow coloured when unlit leading me to guess that they might actually be a Gallium Nitride lightsource stimulating yellow phosphors. In this video I pop the lid on the yellow lamp and test the forward voltage of one of the LEDs to see which technology it uses.
Clive, I bought some GU10 bulbs that look a lot like those, and one started blinking after a few months of use. Any idea what I should look for to correct the blinking?
These are probably AlInGaP as that is what high brightness LEDs on the red end of the spectrum tend to use nowadays. I have heard of blue dies and separate phosphor being used in some green very high brightness LEDs, but that is because the additional gallium in the InGaN die that shifts its light to the green also greatly reduces its efficiency.
AlInGaP also tends to be colored instead of the clearish white of InGaN.
Hey Clive, can you tell me exactly where you got those LED lamps from? I have access to a spectroradiometer that would answer if they are heavily phosphor coated blue dies. The hackish way is use a blue filter gel with a sharp cut off and see how much comes through, but I wouldn't trust it to much. Cool video 🙂