Become a fan of Slashdot on Facebook


Forgot your password?

Comment Re:'Wireless charging' is for fools (Score 1) 120

Cool, does that mean I can get infinite power out of it as long as I can get the receiver and transmitter arbitrarily close to each other? Sounds like each time I cut the distance in half I get twice the power. Zeno saves the day!

If distance=0 represents a theoretical "full power", then how do you double that distance to get the half (or quarter) power according to the inverse law? If some distance > 0 represents "full power", then getting the TX and RX that close ought to be free of this nasty inverse square business.

Comment Re:'Wireless charging' is for fools (Score 1) 120

Induction charging, even at its best, is only about 40% efficient and that's practically touching coils together.

Sure, but that loss isn't due to any inverse square law, is it? Like you said, the coils are practically touching. The op was implying that all wireless charging is stupid because loss increases with the square of the distance. I'm saying (with no research and little expertise in the area) that all of the wireless charging I've seen operates in the near field; and while I don't know how much that 40% efficiency number you gave could be improved upon, I doubt that the dominating factor in the loss is distance in this specific case.

Comment Re:'Wireless charging' is for fools (Score 1) 120

The Inverse Square Law fully applies to any sort of wireless charging because physics works.

I'm pretty sure the fact that most wireless charging systems operate in the near field and rely and near field effects means that the inverse square law doesn't "fully apply". Even if it does in a technical sense, the distance between transmitter and receiver is very small.

Comment Re:I am not able to find that disproof (Score 1, Informative) 270

There's nothing to be disproved. The submitter is just showing ignorance. I was able to find a commencement address by Arno Penzias where he shows the audience what a staggeringly large amount of time we are talking about when we talk about monkeys (or computers) randomly recreating text of any appreciable size. Tip to the submitter: Don't use phrases like "mathematically impossible" unless you really know what you are talking about. Slashdot readers fall all over themselves in their hurry to assert their superiority in these kinds of cases.

Comment Re:so the new clock is 3x as accurate as the old o (Score 2) 127

Several of the sciences depend on extremely accurate timing. It's not a question of seconds lost over millions of years, but rather "how accurately can I time an event that is only a few nanoseconds long", or even better, "Exactly how far apart were these two events, even if the events are separated by hours, or days". It's misleading for the media to talk about timing in the way that they do, but apparently normal people's brains explode when someone says "nanosecond" or "parts per billion".

Slashdot Top Deals

"Bond reflected that good Americans were fine people and that most of them seemed to come from Texas." - Ian Fleming, "Casino Royale"