ive been thinking for a while, since we managed to transfers some data wireless ie. wifi, 3g, and things like that, and i do know that it uses radiowave. but the question here can we actually transfers power wirelessly? what i meant here is transferring the electricity wireless mean you have an adaptor that plugged into wall socket and the receiver is connected to device which received the power wirelessly. This is just some thought of mine. I dont know whether its possible or not. If you dont mind, please discuss.

This post has been edited by Shah_15: Mar 22 2010, 02:25 AM

There's a lot of research are done regarding this

I think some of them did success, I remember I watch it on discovery or something, it just that the cost of implementing it is more expensive than having cables.

http://en.wikipedia.org/wiki/Wireless_ener...o_and_microwave

The problem is efficiency. Conversion factor aside, a lot of power is lost when we send it over the air. We would need a huge power source to transmit over any meaningfully large distance. Transmitting data requires power on both receiver and transmitter side btw.

Saw a research some time back using laser to transmit power that can keep a specially designed lightweight hobbyist airplane continuously in the air, as long as the beam is not interrupted. The plane just flew in circles a couple of feet in the air.

Sure it is possible.

I think photoelectric will be the best to answer your question.
When electrons r emitted from the target metal.
The answer u r searching is there.

infrared is possible right?

nothing is impossible.

transmission of electricity by means of electromagnetic waves is possible. however, dont expect it to replace wires and high voltage cables anytime soon. the low efficiency and potential radiation danger means it would most likely be used short range to charge low voltage devices (cell phones, ipods, etc)

think i watched and read abt this loooong time ago.. yes, it's possible frm what i remembered.. but the drawbacks are : radiation and takes too long do even charge a small amt of energy to that device..

search nikola tesla's experiment

Energy need a medium to be transfered.in this case you may refer it to the air.so, the most suitable method to transfer the energy is by utilizing the optical or radio wavelength.it has been applied in many apps such as remote sensing. since there are some limitation like absorption and scatering in using optical wave, so radiowave is the best method. the problem might be arise now is 'how to carry electric by the radiowave'

Hi All,

interesting discussion.

however, a few basic things we need to know:

1) Electricity consists of:

a) Voltage - Potential difference between 2 points
b) Current - the flow of energy (electron flows at the opposite direction - current was discovered/established b4 electron)
c) Impedance - the resistance to the current flow in a medium

Comparing to water:

Water at the reservoir high above the hills has potential energy. Water flows downward to a lower area thru water pipes. The size of the water pipes determine the amount of water flowing thru it. Can we transfer water without pipes? Maybe in the future?

2) In order for electricity to flow, we need a medium or "conductor" (the "pipes"). Without the pipe, water will get splashed everywhere & some areas might be flooded & ppl drowned (hazard!). Same with electricity.

3) While conductor is used for transfer of current (i wont refer to electron on sub-atomic level), we need insulator to protect the surrounding from getting electrical shock and flash-over. Short-circuit is a fault that is not desired in electrical system. it is similar to water leakage in the pipes.

4) Air is an insulator. If current flows thru air, it's an "arc". Arcing occurs when very high current flows thru the conductor and it ionized the air and caused the dielectric (insulator) breakdown. it will find the closest path to ground/earth/another conducting path to complete the circuit. This is similar to lightning phenomenon.



In practice, we do not want "arcing" to occur because this is electrical hazard. Very high current is flowing thru and a lot of heat is generated.

While i cannot foresee the future (anything is possible), at the time being, electricity must be channeled thru a conductor and protected by insulators.

Electricity is different from data transfer.

Thanks.

1. Energy doesn't necessarily needs a medium to be transferred. E.g. light and radiowaves can travels through vacuum and vacuum-like condition in the space.

2. Like I mentioned earlier, the problem is efficiency. Say you use 1W to send out a radiowave, how much of that 1W is received by the intended receiver? 0.1W? 0.01W? or 0.001W?? Why is radiowave not a good idea? Because it is transmitted in broadcast method i.e. the energy will be spread out over a large area where most will be lost.

3. Radiowave is a form of energy. Converting this back into electricity is simple and done everyday by RF receivers. There's no such thing as carry electric on radiowave.


You have it right about electricity but got it wrong about power transfer.
1. Power transfer doesn't means we need to use electrical current. Using electricity for wireless power transfer would in fact be very stupid because we already know electricity doesn't conduct well at all over the air.

2. Electricity is a form of energy, similar to sound and radiowaves. Whether we used it to transfer data or power, that's totally dependent on the application. E.g. the 240v power cord connected to the TV, that's purely for power transfer only. Or the way we capture sunlight on solar panels to charge up a battery, in which case power is being transferred using light waves over the air.

3. Also, there's nothing that says we cannot extract power from wireless data. In fact, that's exactly what touch'n'go transceiver and many other access card does. Power transfer of this type is only over very short range and for very low power application only.

false.

what is the medium of transfer for light which can travel fine in a vacuum

A very interesting discussion. MIT has/had been conducting research about this i reckon.

I LOLed at the "Power transfer doesn't means we need to use electrical current".

I guess there is nothing more i can say until u read about P=IV

I rest my case. hva nice day.

Nikolai Tesla started transfer 'power' wirelessly around hundred years ago. Only later people put data, protocal and different frequency in these 'wireless power' then became 3G, wifi etc...... So it is the other way around.

This post has been edited by locke: Mar 28 2010, 12:59 AM

Maybe you guy a bit slowpoke liau. Read here -->

http://forum.lowyat.net/index.php?showtopic=1150990&hl=

I thought about this also the last time. It will be brilliant if this concept would come to reality. Imagine charging our phones without cables.

Actually "wireless power" up a device is already been using for many many yrs. And this thing is around us and some of us using it daily. Just we don't realise it.

The touch n go card and the passport chip that been scan is using wireless power to powerup the chip memory and record your data. Nothing special inside. Just the coil and some chip.