Wireless transmission of electricity?

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Main Question or Discussion Point

Is it physically conceivable the possibility of transmitting electricity between spatially separated objects (e.g. a few meters) in a wireless way?
 

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  • #2
fss
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  • #3
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Thanks, interesting!
I didn't read it in full yet, I will asap but it seems at the moment it's limited to very low currents at short distances.
I was wondering, the main drawback of electric cars is their limited autonomy range and long recharging time. If roads could be populated with some sort of "antennas" which could feed electricity to the car as it drives along, those problems might be overcome.
 
  • #4
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Tesla thought it was possible. He was an amazing inventor, but he couldn't turn his ideas into a profitable product, and as a result, died broke. You should read up on his research and ideas for his theories on the electromagnetic field in the earth and on wave energy.

I watched a mythbusters that tested Teslas ideas on energy waves with harmonics. Actually it was a pneumatic jackhammer on a bridge. Adam and Jamie knew they had the right resonating frequency when the 2 lane 200 ft bridge they were on started shaking uncontrollably by their 40 lb. machine. Very good example of his theory.

Just as they used waves to shake a bridge, you can also use electrical waves to send electrical currents through the ground very long distances. The only problem with it is that theres no way to regulate it and make money.

Maybe on Mars.....
 
  • #5
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He was an amazing inventor, but he couldn't turn his ideas into a profitable product, and as a result, died broke.
I don't know about that. I think that whole alternating current thing worked out pretty well. He died broke because he never focused on his finances and his OCD and senility got the best of him.
 
  • #6
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I've seen that there were already some other threads on the subject, TX
 
  • #7
berkeman
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I've seen that there were already some other threads on the subject, TX
Yes, and the "Similar Threads" window at the bottom of this page lists a few that you can check out.
 
  • #8
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Electricity is not "transmitted" in the scenarios described.
That would be a "spark gap" or "lightning"

Rather, it's the transmission and absorption of EM waves which are then locally coverted to moving electrons in a medium sensitive to do this.

A radio antenna is no more receiving actual electrons from an outside source than a solar cell is.
 
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  • #9
davenn
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Electricity is not "transmitted" in the scenarios described.
That would be a "spark gap" or "lightning"
Rather, it's the transmission and absorption of EM waves which are then locally coverted to moving electrons in a medium sensitive to do this.
A radio antenna is no more receiving actual electrons from an outside source than a solar cell is.
This is so true, and the losses are so great that I still cant figure out why people are spending so much time on it ??? pumping a zillion Watts into a transmitting antenna just to see a few mW of induced power in the receiving cct

I really dont get it... it definately isnt economic

Dave
 
  • #10
Born2bwire
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This is so true, and the losses are so great that I still cant figure out why people are spending so much time on it ??? pumping a zillion Watts into a transmitting antenna just to see a few mW of induced power in the receiving cct

I really dont get it... it definately isnt economic

Dave
For any kind of appreciable distances, no it's not worth it (although you could argue it does just fine in the case of a crystal radio). But there are serious and legitimate commercial attempts in doing so for very short distances. This is useful when we wish to charge batteries on multiple compact devices or in devices that are not easily accessible. For example, it would be nice if my ebook reader, cell phone, Gameboy, and mp3 player all could use the same charger instead of having a different charges for each one. Instead, we can just make a dish or platform where we can deposit the objects and they would be charged as they sit. Or medical implants are a key application so that we can charge the batteries of an implant, say a pace maker, without the need for surgery to replace the batteries or to have some kind of port exiting the skin.

But all of these are again very short distances, most would use the term inductive charging as opposed to wireless since the electromagnetic waves are not meant to propagate.
 
  • #11
davenn
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But all of these are again very short distances, most would use the term inductive charging as opposed to wireless since the electromagnetic waves are not meant to propagate.
Ahhhhhh and there-in is the truth to what is really going on ;) exactly There are more and more products around the home using such systems from my electric toothbrush for charging its battery to the electric jug for boiling water.

But I get the impression from what I see on the various forums around the net, that people are expecting to be able to wirelessly transfer significant power levels over significant distances. I really wonder if they understand the drop off of power levels cuz of the inverse square law [PLAIN]http://en.wikipedia.org/wiki/Inverse-square_law[/URL] [Broken]

cheers
Dave
 
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  • #12
Born2bwire
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Ahhhhhh and there-in is the truth to what is really going on ;) exactly There are more and more products around the home using such systems from my electric toothbrush for charging its battery to the electric jug for boiling water.

But I get the impression from what I see on the various forums around the net, that people are expecting to be able to wirelessly transfer significant power levels over significant distances. I really wonder if they understand the drop off of power levels cuz of the inverse square law [PLAIN]http://en.wikipedia.org/wiki/Inverse-square_law[/URL] [Broken]

cheers
Dave
Oh yeah. I quite forgot that my electric toothbrush does charge itself by a handy holding tray. But alas I still need to plug in my electric shaver, Kindle, mp3 player, cell phone, Gameboy. At least I have a wired mouse so I don't need to have another charge for the bloody mouse. Personally I am not holding my breath for this to happen anytime soon. Having a universal inductive charger would require a cooperation between companies that I am not going to hope for.
 
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