LEDs and CRs

[stevo1210]

I have a basic electronics questions so here goes.

Are LEDs (as in the light emitting diodes) cathode rays?

My friend said that LEDs are cathode rays but I've tried googling it up and haven't found anything on that. I'm not going against what he says, but I would like to know if this fact is true.

Thanks.

[Gianni]

Re: LEDs and CRs

Can this article answer to your question?

Ciao
Gianni

[Wizard]

Re: LEDs and CRs

LED emit light by electron collisions that emits when electrons falls back from upper orbit levels at the very narrow region. All solid state, no need for vacuum.

CRT is a vacuum bottle uses stream of electrons emitted from hot heater and repelled by cathode voltage fields and HV fields to slam into phosphors thus glow.
Plasma relies on this as well except done different ways. Fluorsecents, CRT and other arc lighting is all forms of using electrons in flight to stike another kind of atoms or just electrons alone (pure arc) to make light.

Cheers, Wizard

[stevo1210]

Re: LEDs and CRs

Yup, the article answers my question. And so LEDs are cathodes after all.... unless I misread something.

[Wizard]

Re: LEDs and CRs

Yes, LED is another kind of diode but the P N junction is done differently to emit protons (light of specific range of frequency) and done in solid state while other technologies use either vacuum or gas filled tubes in different ways to make light.

Cheers, Wizard

[Toasty]

Re: LEDs and CRs

#1 - What moron on crack decided light blue printing on a white background was the way to build a web page.

No. They are not cathode rays. As the article says, they are photon emitters. i.e. visible light. They carry no electric charge and can not be bent or directed by a magnetic field or voltage.

Cathode rays (actually electron beams) are the stream of electrons leaving the cathode (negative electrode) in a low pressure gas environment such as a vacuum tube. They do carry an electric charge and in a CRT are created in a hot electron stream as Wizard explained in #3 above. Because they are electrons, they can then be directed by voltages and magnetic fields. See also particle accelerators.

Toast