Need Help! Urgent! Circuits

Thread Starter


Joined Mar 14, 2009
Hi everyone,
I'm really terrible at RLC circuits etc, these are two problems I'm having trouble with. I have attached schematics of them.

The first circuit, it says use thevenins theorem, determine the I in the 15
Ω resistor and the voltage Vab of the AC circuit. I know I am meant to use a delta star transformation to determine the thevenin impedance, but I just don't know where to start!

The second circuit says to use norotns theorem to determine the current in the 15
Ω resistor of the AC circuit. Again I don't know why but when it comes to using capacitors and angles etc in circuits, i get confused!

Please someone help, a step by step guide to solving these circuits?



Last edited:


Joined Dec 5, 2009
I thought classes WERE step-by-step guides to solving these problems?

Oh, school kids.

Where are you having the trouble?

What have you done so far?