You know those crystal sets that people played with many years ago? They enabled you to listen to radio using a high impedance earphone, without a battery, because the radio waves induce a small voltage in the circuit (forgive me if I don’t understand it fully)
Well, I’ve often wondered why thousands or even millions of these circuits couldn’t be connected in series to give us some free meaningful power. If someone could explain..
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Those radio waves did not simply appear out of nowhere. Every bit of power that the receiver obtains is part of the power sent out by the broadcasting antenna. So there is no “free” energy there – it came from something that was designed to send out that energy.
There is also the problem of scale. A small antenna gets perhaps a milliwatt or more likely several hundred microwatts. A million of them working perfectly efficiently (which it won’t – since they would interfere if too close together) delivers less than a kilowatt (an average household uses more than that). So much energy would be lost in transmission that it would take the transmitter tens or hundreds of kilowatts to even achieve this FOR ONE HOUSE.
In other words, very expensive, very inefficient, very large and not very useful. We haven’t even touched on the dangers of scaling it up to handle more than one home.
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