# First order Circuit

1. Nov 17, 2012

### Jebus_Chris

I'm not sure what happens when you replace the inductor with a short circuit. The current source is what throws me off.

One thought I had was that you can remove the 6 and 2 kohm resistors, but then I don't know what ahppens to the current source.
http://imgur.com/lks7y
Thanks

2. Nov 17, 2012

### aralbrec

Everything you've said is right. The voltage across the inductor being 0 also means some current is flowing through the 3k resistor. The current source demands a certain current flow, so KCL should give you the inductor's steady current.

3. Nov 17, 2012

### Jebus_Chris

So then are you saying that you remove the current source as well since the voltage around it is zero?

4. Nov 17, 2012

### aralbrec

The question is designed to trick your intuition. A current source can pull any amount of current no matter what the voltage across it is, including 0 volts.

What you've said about the 2k and 6k resistors is correct -- the voltage across them is zero so Ohm's law gives zero current through them. The current source continues to draw 5mA no matter what.

Last edited: Nov 17, 2012
5. Nov 17, 2012

### Jebus_Chris

Ok, so then you're saying that there is 2mA of current traveling up [i(0) = -2] through the inductor?

6. Nov 17, 2012

### aralbrec

Yes, that's it.