catman Posted December 28, 2019 Posted December 28, 2019 G'day all, I hope all are enjoying the Christmas/ New Years break. A bit of a strange one to me! I recently bought a packet of assorted LED's of different colours that I have retrofitted to various power supplies and such and whilst they all work fine I am curious about one thing....their colour when actually illuminated and I am wondering about how LED colour is determined? Some LED's that I have seen have a clear envelope but glow a specific colour, and as in the case of these assorted LEDs, the envelope is already coloured and in the case of one of these LEDs, the envelope is clearly 'orange' but glows a definite 'red'. To me that is somewhat weird. So just how is LED colour determined when energised? Any comments on this? Regards, Felix.
Monkeyboi Posted December 28, 2019 Posted December 28, 2019 It's the semiconductor materials used that determine the emitted colour wavelength. Cheers, Alan R. 1
Monkeyboi Posted December 28, 2019 Posted December 28, 2019 (edited) I knew I'd seen this somewhere. This chart may help explain the various semiconductor materials, doping and additional substances used in the manufacture of coloured LEDs. Cheers, Alan R. . Edited December 28, 2019 by Monkeyboi 1
Peter-E Posted January 15, 2020 Posted January 15, 2020 Voltage is also an issue with changing colours. The voltage required does vary from colour to colour
audiofeline Posted January 16, 2020 Posted January 16, 2020 (edited) Also of interest is the bi-color and tri-color LED's. I think the direction of the current determines the colour the LED glows. A bicolour LED is in my Source turntable - green for 33rpm, red for 45rpm. eg https://www.jaycar.com.au/bicolour-red-green-5mm-led-45mcd-round-diffused/p/ZD0250 https://www.jaycar.com.au/tricolour-red-green-10mm-led-10mcd-round-diffused/p/ZD0255 Edited January 16, 2020 by audiofeline
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