- LED’s don’t produce white light in the same way that incandescent lamps do.
- One LED cannot produce the full range of colours that sunlight or incandescent light produces.
- A LED typically emits a single colour of light which is composed of a very narrow range of wavelengths.
- However LED’s emitting the three primary colours of red, green and blue light can be combined to produce white light.
- By changing the relative intensity of the primary colours, a multi-colour LED produces an extremely wide range of colours.
- An LED light source is often used to demonstrate the effect of projecting primary coloured lights onto a dark surface because they emit light in very narrow bands of wavelengths. The peak wavelength for the selected lights might typically be red = 625 nanometres, green = 500 nm, blue = 440 nm.