Timeline for Is this true: "At over 700 Hz, current simply flows over your body"?
Current License: CC BY-SA 3.0
15 events
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| Jul 4, 2020 at 9:06 | vote | accept | Pawan kumar | ||
| Apr 13, 2017 at 12:32 | history | edited | CommunityBot |
replaced http://electronics.stackexchange.com/ with https://electronics.stackexchange.com/
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| May 19, 2015 at 8:32 | comment | added | Criticizing Israel not allowed | @tomnexus AFAIK "lively discussions" are very much off-topic. | |
| May 19, 2015 at 5:44 | comment | added | tomnexus | @LorenPechtel that is a very good point. Why don't you ask it as a new question? Apart from the shock safety, transformers and smoothing capacitors could be much smaller. Rotating machines would need a lot more poles. Core losses would go up. Skin effect would increase losses. Line charging current up 20 times. And imagine the constant hum. Aircraft use 400 Hz. Might be a lively discussion if you ask it right. | |
| May 19, 2015 at 5:13 | comment | added | Loren Pechtel | I take it that using a 1khz mains supply would cause enough other headaches that it's not worth the safety benefit? | |
| May 19, 2015 at 4:50 | comment | added | tomnexus | @AndrewT there are some high voltage, low current applications, which are less dangerous than household mains. Laser printers, for example, with their 500 to 2000 V, are not nearly as scary to me as a 2 kV power line. | |
| May 19, 2015 at 4:22 | comment | added | Andrew T. | I'm interested in the explanation for the last paragraph, "almost always more dangerous". Are there any occurences where higher voltage is not dangerous? Edit: I think I get the idea of electrosurgery from steveverrill's answer. | |
| May 19, 2015 at 0:49 | comment | added | Criticizing Israel not allowed | For the second-to-last paragraph: Note that we use lower current at higher voltage when we're trying to keep the power the same. But the power doesn't naturally stay the same if you just increase the voltage without changing other things as well. | |
| May 18, 2015 at 16:47 | comment | added | The Photon | @TomCarpenter, Skin effect is directly related to the attenuation that an applied wave would see due to the conductivity of the material. | |
| May 18, 2015 at 15:26 | comment | added | ARMATAV | @TomCarpenter He's got your reference, but those inductive fields are vibrating the water molecules, because at high frequency the 'skin effect' also means that the AC can penetrate a 'skin depth' down into the conductor. If you have a 10mm thick box, and the skin depth of your current applied to the box is 1mm, most of the current is in the 1mm thickness of the outer edge. But if you leave that box in a microwave, and you shoot waves at it that have a skin depth of 2mm, most of the current will be in the first 2mm of the box, not the first 1mm. It's the signal, not the conductor, that does it | |
| May 18, 2015 at 14:11 | comment | added | tomnexus | @TomCarpenter Here is a paper with some figures for skin depth in people. It's a bit shallower than I thought, but not too far out, 12 mm at 900 MHz, 7 mm at 2400. The heating effect is directly related to both the E field and/or the current, so is confined mainly to a skin depth or two. | |
| May 18, 2015 at 13:50 | comment | added | Tom Carpenter | Do you have a reference for your comment on the skin effect and microwaves in meat. It seems to be that the effect should be more to do with attenuation - the microwaves heating the mean means energy is being lost to vibrating water molecules. The skin effect is about electromagnetic induction causing currents of electrons to move to the surface of the conductor. | |
| May 18, 2015 at 13:47 | comment | added | mskfisher | Upvoting specifically to promote the debunking of the "high voltage is safer" myth in the OP's question. | |
| May 18, 2015 at 13:01 | history | edited | tomnexus | CC BY-SA 3.0 |
Added comment about high frequency current
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| May 18, 2015 at 10:19 | history | answered | tomnexus | CC BY-SA 3.0 |