# RLC V,I Expression

Discussion in 'Homework Help' started by Mark Speer, Mar 16, 2010.

1. ### Mark Speer Thread Starter New Member

Mar 16, 2010
1
0
Hello guys, I need some help with this HW problem.

The problem got a current source (Is), 5ohm resistor, 8mH inductor and a 2mF capacitor. All the components are in parallel with each other respectively. The current for the Inductor was given as
IL= 10(1-e^-625t)A ( L-current arrow flows top to bottom)

1) First question is to determine the expression for V across the capacitor. ( + at the top node and negative and bottom)

My solution was Vc = 1/c ∫10(1-e^-625t) dt
=1/2mF ∫10(1-e^-625t) dt

2) Question 2 is determine the expression for the current through the capacitor

I know Ic= C dv/dt
Therefore Ic = 2mF [ 10(1-e^-625t) dt] ......is this right? I cant think of anything else :-(

3) Last question is to determine the expression for (Is) ( current source)

in the schematics, (Is) is flowing from the bottom to the top node.

How do I go about getting Is :-( ?