Timeline for Non-metal cases
Current License: CC BY-SA 2.5
10 events
when toggle format | what | by | license | comment | |
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Apr 28, 2010 at 20:54 | comment | added | CH | Wikipedia lists the Electrical Resistivity of Aluminium at 20DegC as '28.2 nΩ·m' which is 28.2 (0.001)uΩ.(100)cm = 28.2 (0.1)uΩ.cm = 282 uΩ.m amirite? :> so my value was off by 1.8 | |
Apr 27, 2010 at 21:32 | comment | added | pingswept | Ah, wait, my answer should have been 104.89 uinches, not um. In um, it's 2.66 um, which makes more sense-- exactly 10x off from your answer, and the resistivity is square-rooted in the calculator. | |
Apr 27, 2010 at 21:30 | comment | added | pingswept | Hi CH. I think your resistivity is off. It should be 2.802 uΩcm. I suspect you misread uΩm as uΩcm. I get 104.89 um for 1 GHz using 2.802 uΩcm and 1.00002 for permeability. Does that seem right to you? | |
Apr 27, 2010 at 20:52 | comment | added | Chris2048 | Ignore the "– CH 2 mins ago" above :-/ | |
Apr 26, 2010 at 15:23 | comment | added | CH | Using the values 280.2 uΩ*cm for resistivity and 1.00002 for rel. permeability (for Aluminium) with the calculator posted above, I get: 1Hz -> 0.843 m, 60Hz -> 10.876 cm, 20KHz -> 5.957 mm, 1MHz -> 0.843 mm, 1Ghz -> 26.64 um, 2.4GHz -> 17.2 um, 5.8GHz -> 11.06 um, 10GHz -> 8.42 um. Although, someone please check my working, I can't be sure of any of the above. – CH 2 mins ago | |
Apr 26, 2010 at 15:22 | comment | added | CH | Another good question, what kind of frequencies do we need to block? That is, What kind of radiation might there be externally that may be harmful to the computer, and what frequencies will the computer itself generate that need to be prevented from escaping? | |
Apr 25, 2010 at 2:09 | comment | added | Earlz | So according to that calculator, to block 60hz a single sheet of aluminum baking foil isn't thick enough correct? | |
Apr 24, 2010 at 22:30 | comment | added | pingswept | You can calculate skin depth here: microwaves101.com/encyclopedia/calsdepth.cfm The depth decreases as frequency goes up. One implication of this, if I understand it correctly, is that low-frequency noise, like 60 Hz hum, is difficult to block. | |
Apr 24, 2010 at 22:03 | comment | added | CH | Nice answer, thanks, although what are the frequencies that is based on? I wonder if there is any way to test this? | |
Apr 24, 2010 at 20:20 | history | answered | pingswept | CC BY-SA 2.5 |