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While studying inductors, I learned that it will take some time for current to reach it's rated value \$ I\$, and considered in "steady state".

Is the same applied for singular wires(not forming a loop/multiple turn loop)? In general, if a wire with low resistance and possibly low inductance had DC flowing, will it time a short duration of time to reach maximum current? Using this equation: \$ t = \frac {L}{R} \$.

From the equation above, that's the time it takes for current to reach \$ \frac {2}{3} \$ it's value?

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    \$\begingroup\$ Can you please clarify what you mean by "not form a loop"? A loop and a coil are separate concepts. Draw a picture if that helps. \$\endgroup\$ – Wossname Sep 17 '16 at 11:09
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Is the same applied for singular wires(not forming a loop/multiple turn loop)?

The example you ask for consideration is an imposibility. If a wire passes current then it MUST have a return path to the signal source and this forms a loop. Even a monopole antenna passes current and has a return path even though physically it looks like a wire with a connector at one end.

Having made my rant, you can theoretically predict that a wire does have self-inductance and that inductance is maximum when the "return path" is a gazillion miles away: -

enter image description herehttp://latex.eeweb.com/eq.latex?L%3D2l%5Cleft%20(%20%5Cln%20%5Cleft%20(%20%5Cleft%20(%20%5Cfrac%7B2l%7D%7Bd%7D%20%5Cright%20)%5Cleft%20(%201%2B%5Csqrt%7B1+%5Cleft%20(%20%5Cfrac%7Bd%7D%7B2l%7D%20%5Cright%20)%5E%7B2%7D%7D%20%5Cright%20)%20%5Cright%20)-%5Csqrt%7B1+%5Cleft%20(%20%5Cfrac%7Bd%7D%7B2l%7D%20%5Cright%20)%5E%7B2%7D%7D+%5Cfrac%7B%5Cmu%20%7D%7B4%7D+%5Cleft%20(%20%5Cfrac%7Bd%7D%7B2l%7D%20%5Cright%20)%20%5Cright%20)

Where "l" is the wire length and "d" is the diameter.

From the equation above, that's the time it takes for current to reach 2/3 it's value?

No, it's not two thirds it's 0.63212055882 or \$1-e^{-1}\$

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  • \$\begingroup\$ I wonder if the OP should have used the term "form a coil" instead of "form a loop". A coil will experience a slower rise time (due to back-EMF in adjacent turns of wire) than a straight section of wire all other factors being equal. Straight sections of wire (such as a trace on a PCB) will have a rise time due to the fact that real physical circuits are subject to unwanted phenomena such as capacitance and other minor annoyances. \$\endgroup\$ – Wossname Sep 17 '16 at 10:56
  • \$\begingroup\$ The OP said NOT forming a loop \$\endgroup\$ – Andy aka Sep 17 '16 at 11:03
  • \$\begingroup\$ Andy, yes I think it might be a nomenclature issue. I think the OP is talking about inductors and straight wires (eg going from one terminal of a battery to the other without any formed coils in it). The OP may be using "loop" and "coil" synonymously when that might not be the intention. \$\endgroup\$ – Wossname Sep 17 '16 at 11:08
  • \$\begingroup\$ I fail to see the relevance of your observation on my answer. Sorry! \$\endgroup\$ – Andy aka Sep 17 '16 at 11:42
  • \$\begingroup\$ I didn't mean any offense. \$\endgroup\$ – Wossname Sep 17 '16 at 11:46

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