# could electricity be transported through thin air **URL:** \ **Category:** Factual Questions\ **Created:** [December 12, 2002, 7:23pm UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308 "2002-12-12T19:23:12Z")\ **Posts on this page:** 15\ **Page:** 2
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [December 12, 2002, 10:54pm UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/21 "2002-12-12T22:54:25Z")
> [@](#): > > _engineer\_comp\_geek wrote:_ > RF power is used today in small amounts. If you’ve ever seen one of those easy-pass toll systems, or you have an RF tag ID card system where you work, these are often beam powered devices. The radio beam hits the card, and intially just about all of the energy goes to charge up a capacitor. Once the thing is charged the intelligent chip inside switches on and uses that power to send back a coded pulse stream (also modulated to RF frequency), which sends the number coded into the card back to the reader. The main reason they are beam powered is so they don’t ever need to have their battery replaced. Battery versions are also available for longer range systems. You sure about that? The ones they use here in Texas (and in Oklahoma) are not RF-powered, but instead have a very-low-power consumption circuit which can vary its reflectance, therefore modulating the RF received back at the base (see [http://www.amtech.com/technology/techapps.htm](http://www.amtech.com/technology/techapps.htm) ). I believe that the internal workings are powered by a long-life battery. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [December 12, 2002, 11:01pm UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/22 "2002-12-12T23:01:14Z")
Please, let’s not get confused with using RF energy to transmit _information_ vs. using RF energy for the sole purpose of transmitting _power_. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [December 12, 2002, 11:29pm UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/23 "2002-12-12T23:29:05Z")
> [@](#): > > \*Originally posted by levdrakon \* > **The solar power satellite idea is alive & well, it seems. [Space.com article](http://www.space.com/businesstechnology/technology/solar_power_sats_011017-1.html)** Regarding the link… I’m going to go off on a limb and say this the _ **stupidest** _ thing I’ve ever heard of. Has anyone performed a complete _system efficiency analysis_ of this idea? I want to know: - The total amount of energy (in watts) expended to manufacture the satellites. This will include the energy expended during _all_ phases – R&D, design, testing, prototyping, and manufacturing. - The energy expended getting the satellites into orbit. This will include energy expended to manufacture “one time use” hardware, and (obviously) fuel. - Amount of solar energy collected. - Efficiency of converting solar energy to laser or microwave energy (onboard the satellite). - Efficiency of converting laser or microwave energy to electrical energy (on the ground). - Projected lifetime of satellites. After you take all these things into account, I am _ **extremely** _ confident you will find that much, much, much more energy will be expend that whatever energy you might get out of it. Pure stupidity… ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [December 13, 2002, 12:16am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/24 "2002-12-13T00:16:31Z")
THe new tablet PCs rely on the base station briefly charging the capacitor on the pen to write. This means you can move the mouse while the pen is 5cm off the tablet and also never run out of batteries. Pretty cool IMHO. ---
**Author:** ![bouv](https://avatars.discourse-cdn.com/v4/letter/b/bc8723/32.png) [@bouv](https://boards.straightdope.com/u/bouv)\ **Post date:** [December 13, 2002, 12:24am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/25 "2002-12-13T00:24:51Z")
There’s also new watch (I forget the brand) that recharges it batterries on a base station while never having physical contact between the battery and station…I think. It’s simialr to the tablet PC thing **Shalmanese** talked about. ---
**Author:** ![TheNerd](https://avatars.discourse-cdn.com/v4/letter/t/858c86/32.png) [@TheNerd](https://boards.straightdope.com/u/TheNerd)\ **Post date:** [December 13, 2002, 12:54am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/26 "2002-12-13T00:54:57Z")
> [@](#): > > \*Originally posted by Shalmanese \* > \*\*THe new tablet PCs rely on the base station briefly charging the capacitor on the pen to write. This means you can move the mouse while the pen is 5cm off the tablet and also never run out of batteries. Pretty cool IMHO. \*\* That’s 0.5cm, and the “base station” is the tablet itself. I get to play with these at work. It would be really annoying if the mouse had to move 5 cm off the tablet to stop tracking. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [December 13, 2002, 2:06am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/27 "2002-12-13T02:06:36Z")
> [@](#): > > \*Originally posted by Crafter\_Man \* > **Has anyone performed a complete _system efficiency analysis_ of [solar power satellites]?** The answer is in the quoted article, namely: > [@](#): > > In summary, the NRC panel members noted that for any SSP program to churn out commercially competitive terrestrial electric power, breakthrough technologies are required. > > That being said, even if the ultimate goal of supplying competitive energy is not attained, the experts added: “The technology investments proposed will have many collateral benefits for nearer-term, less-cost-sensitive space applications and for non-space use of technology advances.” Nobody is claiming that solar power satellites are cost-effective with current technology. It’s viewed as an idea that’s potentially useful and worth investing some R&D money on. ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [December 13, 2002, 2:52am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/28 "2002-12-13T02:52:03Z")
Since the OP asks specifically about thin air, it’s worth noting that the thinner the air, the closer to “no” the answer is. Until you arrive at a vacuum, where we get an unqualified NO as the answer. ---
**Author:** ![Urban\_Ranger](https://avatars.discourse-cdn.com/v4/letter/u/e9c0ed/32.png) [@Urban\_Ranger](https://boards.straightdope.com/u/Urban_Ranger)\ **Post date:** [December 13, 2002, 3:00am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/29 "2002-12-13T03:00:26Z")
What? You got it backwards. The thinner the air, the easier it is for arcs to jump, until you have a vacuum, when it becomes the easiest. ---
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [December 13, 2002, 3:03am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/30 "2002-12-13T03:03:11Z")
**Attrayant** , please share with us your definition of electricity, so we can make sense of you post. ---
**Author:** ![Ms2001](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ms2001/32/18463_2.png) [@Ms2001](https://boards.straightdope.com/u/Ms2001)\ **Post date:** [December 13, 2002, 3:09am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/31 "2002-12-13T03:09:28Z")
> [@](#): > > \*Originally posted by bouv \* > **There’s also new watch (I forget the brand) that recharges it batterries on a base station while never having physical contact between the battery and station…I think.** I had an electric toothbrush that charged with no metal contacts between the toothbrush and the base station. It would even work about 1/2" above the base station. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [December 13, 2002, 3:13am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/32 "2002-12-13T03:13:57Z")
**Attrayant** and **Urban Ranger** are both partially correct. When you lower pressure from one atmosphere, it becomes easier to create an arc because ionized molecules can move more freely. But beyond a certain point, you start to run out of molecules that can be ionized, and without them you can’t have an arc. So it becomes harder and harder to create an arc. Moderately high voltage (a few thousand volts) is usually safe to use above 0.2 atmospheres or so, or below 10[sup]-8[/sup] atmospheres, but not in between. This of course depends on the size of the smallest gap, but that’s my rough rule of thumb working with typical laboratory equipment. If you want more details do a search for “Paschen Curve” which describes this relationship. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [December 13, 2002, 3:16am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/33 "2002-12-13T03:16:53Z")
Just to clarify, “safe to use” in my case means no arc is produced. An arc is essentially a short circuit, and if it happens on a sensitive equipment it can cause severe damage. I’ve seen a _very_ expensive detector destroyed by an arc because some gas leaked into the vacuum chamber where a 10[sup]-9[/sup] atmosphere had been maintained. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [December 13, 2002, 4:01am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/34 "2002-12-13T04:01:27Z")
> [@](#): > > \*Originally posted by Crafter\_Man \* > \*\*Please, let’s not get confused with using RF energy to transmit _information_ vs. using RF energy for the sole purpose of transmitting _power_. \*\* I don’t know about the others but I’m not confused. Power is transmitted and power is received in radio transmissions. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [December 13, 2002, 5:05am UTC](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308/35 "2002-12-13T05:05:46Z")
> [@](#): > > \*Originally posted by CurtC \* > \*\*You sure about that? The ones they use here in Texas (and in Oklahoma) are not RF-powered, but instead have a very-low-power consumption circuit which can vary its reflectance, therefore modulating the RF received back at the base (see [http://www.amtech.com/technology/techapps.htm](http://www.amtech.com/technology/techapps.htm) ). I believe that the internal workings are powered by a long-life battery. \*\* Quite sure. There are several different types. There are some that have a permenant long life battery, others that have a battery that you can change, and there are also beam powered ones as well. From this site: [http://www.dragg.net/users/romanj/info/state/rail/aeistandard-technology.html](http://www.dragg.net/users/romanj/info/state/rail/aeistandard-technology.html) > [@](#): > > There are two types of Amtech Transportation Tags, Beam Powered and Battery Powered. The Beam Powered Transportation Tag does not contain a battery. It must get all of the energy needed to operate its internal circuitry from the reader’s RF signal. The beam powered tags are a good example of what the OP is looking for, an instance where equipment is actually powered from transmitted power. The source of power for all of the active components in a radio or television receiver is the wall outlet, not the receiving antenna. [Previous page](https://boards.straightdope.com/t/could-electricity-be-transported-through-thin-air/142308.md?page=1)