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Calculating diamter of wire that will blow if current exceeds 1A

  • #1
Calculating diamter of wire that will "blow" if current exceeds 1A

1. You need to design a 1.0 A fuse that "blows" if the current exceeds 1.0 A. The fuse material in your stockroom melts at a current density of 500A/cm^2.



2. J = I/A



3. J = 500A/m^2 = 50000A/m^2 = 1.0A / (pi*r^2)

r = sqrt[1/50000*pi] = 0.00252 m
diamter = 2*r = 0.005 m = 5.0mm

That is incorrect (answer in mm).
 

Answers and Replies

  • #2
tiny-tim
Science Advisor
Homework Helper
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1. You need to design a 1.0 A fuse that "blows" if the current exceeds 1.0 A. The fuse material in your stockroom melts at a current density of 500A/cm^2.

3. J = 500A/m^2 = 50000A/m^2


Hi Linus Pauling! :smile:

(try using the X2 tag just above the Reply box :wink:)

You didn't use enough zeros to convert from cm2 to m2 :wink:

(but why bother? why not leave it as cm??)
 
  • #3


ahh cripes. thanks for the catch... i always do that. :)
 

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