It’s not a big amount. (For, e.g., a typical mains cable.) And cabling, especially if the currents flowing in it are at high frequencies (which means more radiation), is often designed to reduce that radiation. That’s one reason why we have coaxial cables and twisted pairs. For a 50Hz or 60Hz power cable, though, the radiative losses are tiny.
You can power devices wirelessly—using “those cordless chargers”. They are designed to maximize the extent to which these effects happen, and of course the devices need to be designed to work that way. Ordinary mains cables don’t radiate a lot and it isn’t practical to power anything nontrivial by putting it near a mains cable.
But the most effective way of getting energy from the field around a pair of wires is … to connect the wires into an electric circuit. Indeed, it’s only when they’re connected in such a circuit that the current will flow through the wires and the energy will flow around them.
I recall seeing something about a very low-powered (and cheaply made) LED lightbulb which could never be turned off. With the light switch on, it was bright, and with the light switch off it was much more dim, but not actually off. It turned out this was because in certain common house wiring configurations, electrical field effects between nearby wires allow enough power through to light the bulb
Yeah, I did have that experience too. But come to think of it, his explanation in the video sounds counter-intuitive for AC & DC. With the bulb connected to the mains via a wire (even though it’s the neutral line and that line is severed) like in the better part of the video, as long as the mains is AC the bulb will always at least dim...
It’s not a big amount. (For, e.g., a typical mains cable.) And cabling, especially if the currents flowing in it are at high frequencies (which means more radiation), is often designed to reduce that radiation. That’s one reason why we have coaxial cables and twisted pairs. For a 50Hz or 60Hz power cable, though, the radiative losses are tiny.
You can power devices wirelessly—using “those cordless chargers”. They are designed to maximize the extent to which these effects happen, and of course the devices need to be designed to work that way. Ordinary mains cables don’t radiate a lot and it isn’t practical to power anything nontrivial by putting it near a mains cable.
But the most effective way of getting energy from the field around a pair of wires is … to connect the wires into an electric circuit. Indeed, it’s only when they’re connected in such a circuit that the current will flow through the wires and the energy will flow around them.
I recall seeing something about a very low-powered (and cheaply made) LED lightbulb which could never be turned off. With the light switch on, it was bright, and with the light switch off it was much more dim, but not actually off. It turned out this was because in certain common house wiring configurations, electrical field effects between nearby wires allow enough power through to light the bulb
https://www.youtube.com/watch?v=1uEmX5XClPY
Yeah, I did have that experience too. But come to think of it, his explanation in the video sounds counter-intuitive for AC & DC. With the bulb connected to the mains via a wire (even though it’s the neutral line and that line is severed) like in the better part of the video, as long as the mains is AC the bulb will always at least dim...
TBH I’m a bit more confused :)