Lowest power required to light up an element, be it LED of light bulb or Neon?

What  component (led, bulb, neon...) needs the absolute minimum of energy to light up even dimly ?
What I would like to do is to make something like RFID (no batt) that would be able so sense RF field from some distance, 2-3m.

Thank you.

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lemonie5 years ago

What's this RF field then?
(it makes a difference)

L
nccwarp9 (author)  lemonie5 years ago
As mentioned earlier, lets say you are about a mile from a large radio tower.
I know that radio receivers can be made to work without batteries.
Yes, just build a tuned-circuit with a big aerial. Look up radio receiver circuits.

L
Fluorescent tubes will light quite brightly from leakage currents through the glass, in a dark room.

However, "RF fields" can vary from picowatts to many watts. What (!) have you got available ?

Steve
nccwarp9 (author)  steveastrouk5 years ago
I was thinking more in the line of using RF from big radio towers or power lines. But at the end the most prevalent RF source today are cellphones. There are instructables on how cellphone can light up an LED but its all close.
As I mentioned it, it need not to be bright.
nccwarp9 (author) 5 years ago
I was thinking more in the line of using RF from big radio towers or power lines. But at the end the most prevalent RF source today are cellphones. There are instructables on how cellphone can light up an LED but its all close.
As I mentioned it, it need not to be bright.
iceng5 years ago
See the Video attached where a Simple Finger Move  (Very Low Power)
cause Oxygen to ionize with a spark of Light, by way pressing of two
Cleavite ¼" diameter 1" long  piezoelectric  crystals.  .  .   A
piezzolever.bmp