Lowest Vf LEDs?

[JJHitt]

Anyone know if there are any LEDs out there with a Vf of a volt or less? Preferably much less.

The idea I'm toying with using a LED as the detector diode in a crystal radio. I'd like to have a diode that lights either off of the signal from a local radio station, or from nearby lightning strikes ('sferics).

I'm sure that if it exists, it'll have to red or IR, but I'm interested in know just how low I can go.

 

[Doug Owen]

It's a work function deal, you're right it'll be *far* IR, not visiable. Useless to your task.

FWIW, this can be done, but you need a lot of antenna to get even a few microwatts. You can easily get that at any voltage you'd like (within reason), but the current will be very very low. You'd probably need night vision to see it....

Doug Owen

 

[andrewwynn]

add a high gain transistor and a long life lithium battery to power it, i think you can make your detector.. would run for months or even a year or more on a battery.

 

[danielo_d]

[ QUOTE ]
JJHitt said:
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...off of the signal from a local radio station, or from nearby lightning strikes ('sferics).



[/ QUOTE ]

[ QUOTE ]
Doug Owen said:
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FWIW, this can be done, but you need a lot of antenna to get even a few microwatts.

Doug Owen

[/ QUOTE ]

Just don't make a Lightning rod out of that antenna.
/ubbthreads/images/graemlins/ooo.gif jk.

Sounds like a really cool project. Keep us posted on how it turns out. Good Luck!

Danno

 

[Zelandeth]

Think the lowest Vf visible LED's are about 1.7V (Don't quote me on that though), but I know that some IR LED's have a Vf of around 1 volt.