Finding i(t) (Source Free RL Circuit)

[salman213]

1. http://img529.imageshack.us/img529/6205/87421877rv5.jpg [/URL]3. First I found i(0)

the equation for a source free RL circuit is

i(t) = i(0)e^(-t)/T

T = L/ReqSince the inductor will be shorted when t<0, i(0) must be 5mA.

Now to find Req I added series and parallel appropriately to find

Req = 3/4k Ohms

so my equation is

i(t)= (5x10^-3)e^(-t)/T
where T = (1x10^-3)/(3/4x10^3)can someone please check that, Thanks!

 

[Defennder]

By that arrow pointing to t=0, do you mean that the switch is closed for a very long time for t<0 and is opened at t=0?

 

[salman213]

ya for a very long time (t<0) the switch is "horizontal" then at t=0 it is moved to the lower point.

 

[Defennder]

Yeah I got the same answer.

 

[salman213]

ok great, thanks!