New invention from MIT

Simulating high-Q resonant oscillators with say SPICE often takes a lot more effort than actually building them or just working out their parameters on the back of napkin!

Maybe I can send them sold old literature on spark-gap transmitters and Tesla books? That way they can at least use the modern term for those discs rather than inventing a new name :-).

Tim.

On a sunny day (Fri, 02 Feb 2007 03:19:55 -0800) it happened The Phantom wrote in :

In an other context about human evolution it was mentioned that 'language' was a big help conveying ideas to the younger generation (as compared to apes, who have no language). So as the younsters start playing with electrick-e-ty we will have to convey some of our experiences to them. I thought this was partly a task for eductation, but as more knowledge is accumulated, and more conveyed by languege, and less by actual hands on experiment, maybe human evolution ends here? OK, was just thinking aloud.

EE Times has a page where they announce one or two such stunning breakthroughs every week. I can't recall one of them ever becoming a real product.

John

The math for this was worked out two centuries ago. Magnetic fields drop off as the third power of the distance, relative to the distance between the poles, so sending power by magnetic fields is kinda ridiculous.

Cool! I guess my Braun electric toothbrush can breath a sigh of relief that someone figured out how its battery can get charged -- every week for the past 4 years.

Tom P.

============================ What about hiding a large receiving coil (hidden in a planter) under the power lines out by the mailbox?

You're forgetting neural networks. Oh, wait, we've all forgotten those. How 'bout fuzzy logic?(*)

(*) True story: In line, boarding a plane in the midst of the craze, two fuzzy evangelicals were arguing a finer point of fuzzy logic. "Fuzzy logic?" says I, busting in. "Yes!" they replied, welcoming the fresh meat with carnivorous anticipation. "Ehh ... better than no logic at all, I s'pose," says myself in turn (nearly bustin' up, I had to turn to hide an ear-to-ear Cheshire grin). Stoney silence ensued, a great improvement!

Cheers, James

I've heard of but not read about these guys. AIUI (third-hand), what they propose is something like an array of emitters which combine to produce a certain H-field, which supposedly can transfer power over space without radiating far-field. Cancellation, constructive this- and-that, and other such phrases were bandied about.

A friend referred me to their literature, but I've misplaced the reference. Besides, I prefer to wait for the prototype ;-)

James

That's funny, I was just thinking the same thing. My Sonicare seems to get coupled just fine without wires.

Jim

Nope, sorry, It's aready well covered in several parts of "Wireless Telephony and Broadcasting" by H.M.Dowsett, London, 1923. However, for some reason they missed out any reference to the Laptop.

Barry

But these guys have gone one step further. :-) They could show you how charge it from a few meters away!

But in theory you *could* produce enough near field to do the job. Then you could cook dinner right there beside your laptop while the laptop is being charged!! And, keep yourself warm!! :-(

Didn't those old diathermy machines run at around 13 MHz, in the ITM band?

I remember seeing pictures of a doctor applying the coil to someone's shoulder. The new MIT invention will be able to apply diathermy from a meter away; no need to get close.

It sounds like the (apparently) single-turn loop they're proposing would run in the HF band, sort of like the Iso Loop antenna.

But, but, but, it's not even April yet!

Thanks! Rich

Get the full scoop here:

can you translate it into ordinary english for us mere mortals?

Cheers Terry

I don't claim to understand the paper, but there are some red flags:

(1) Any scientific paper that has lots of "terms" in "quotes" should make a big klaxon go off in your "head". These "air quotes" mean the "writer" can't think of an apropos "word" so they use a bit of "jargon" instead.

(2) A purely theoretical approach isnt terribly helpful. Any proposal to beam microwaves should perhaps keep in mind that you get cataracts pretty quickly from anything much over 5mw/cm^2. Also a lot of people have closed metallic loops, such as pacemaker leads, orthodontia, jewelry, watch bands, and rings on their fingers. It's probably unwise to induce considerable current into these loops.

I thought it was just a variation on a resonant coupled charger?