LED at a certain Frequency

[priestinacloset]

Hello I wanted to build an LED flasher but at a certain frequency.

I used wavelength*freq=c to determine that a light whose max wavelength was 940nm could have a max frequency of 3.19 * 10^14 hertz. My goal was to get a frequency in the 2 Ghz range. I thought i would need to use a 555 timer configured as a multivibrator but I am not certain and was looking for some guidance. Any help would be greatly appreciated.

thanks

 

[MikeMl]

Let me get this staight? You want a 555 to flash a Led On/Off at 2 Ghz??????

Max operating frequency for the 555 is ~1MHz. A normal led can be modulated a few MHz.

 

[priestinacloset]

So is there anything i could use to get that high of frequency out of an infrared led?

 

[audioguru]

Why do you want to flash an LED at such a high frequency?

 

[priestinacloset]

its for a project so educational purposes i guess

 

[ke5frf]

Priest in a closet?
That is a very loaded screen name in this day and age.

 

[Sceadwian]

You can't flash an LED at 2GHZ, due to the amount of time it takes an LED to turn on and off it has a much more limited frequency. In order to operate an LED at 2ghz it would have to be physically so small that you wouldn't be able to visually detect it's output.

 

[audioguru]

But the school teacher does not know the limitations.
Why are there teachers that do not know about what they are teaching??

 

[priestinacloset]

hmm this does not seem to bode well. I appreciate all the input. But don't video game controllers and tv remotes use the Ghz range?

 

[tcmtech]

Nope. A few tens to hundreds of hertz typically.
RF communications however often use multi GHZ frequencies.

I think that some fiber optic communications systems may be using single LED sources that may be modulated in the few hundred MHZ range though.
However I could be misinformed about that though.

 

[Sceadwian]

The IRDA is currently developing IRsimple, the end goal being 100mbits, they've demonstrated 16mbit data rates over IR. I'm sure they use a modern bit encoding method, but worst case scenario even if they used Manchester encoding that would be a maximum modulation rate of 200mhz, and that's pushing the limits.