I am curious as if it is possible to change the color of light being emitted from a light bulb or LED.

The theory is if you were to use a frequency generator, up to above UV hrz, and used an amplifier to power the light bulb, one might be able to change the color of the light emitted.

As a standard filament bulb is powered by DC current, as in a flashlight, the filament gets hot and glows. If a similar filament bulb is powered by AC current like a typical desk lamp, the filament gets hot and glows.

I wonder if frequency would have any effect on how the filament emits light.

I do believe however that with a non-filament light like an LED would change color.

Also what about GAS lights like Neon or other gas tube lights?

Anyone have insight on this? Thanks.

  • $\begingroup$ Changing the frequency of the AC to an incandescent bulb will not change its color. It can be made to glow a dim red or orange with less current so that the filament does not reach white hot temperature of about 1300C $\endgroup$ Jun 23 at 7:01

the thermal time constant of a tungsten filament bulb is of order ~hundreds of milliseconds which means that when driven with 60Hz AC, its light output is continuous and you cannot modulate its color output with an AC source.

  • $\begingroup$ What about in the case of an LED or gas tube? $\endgroup$
    – Noidly1
    Jun 24 at 14:50
  • 1
    $\begingroup$ Blinking light patterns can sometimes fool the human eye into seeing colors where there aren't any. But in any case, what you propose won't work, and I will think about how to explain why in less than 500 words. $\endgroup$ Jun 24 at 15:01

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