ARGH!! 6 circuits problems will be my demise.. WTF am I doing wrong?

[brxndxn]

I have 6 AC circuits problems due tomorrow at 9:35am.. And, I've worked 4 of them so far and I know what I'm doing. However, after the entire page of work on each problem, I am getting the wrong answers on every problem!

Okay.. could there be anything I need to keep in mind? like quirks with phasor representation and the TI 89? Or imaginary number manipulation? I'm doing nodal and mesh analysis with impedances.

This is so damn frustrating. ARGH. /me kills self again.

 

[GiLtY]

Sorry, can't help you here.. not on AC circuilts yet (if it was a DC circuit problem I might be able to help you out).

Anyways, here's a bump for ya.

 

[AznMaverick]

since i hate circuit problems and i know how frustrating it can be. you get a bump from me also.

 

[Syringer]

Ew ew ew ew, I did basic circuit problems in high school physics, and would rather burn my left hand off than try another one.

 

[TuxDave]

*EE Grad student coming to the rescue!*

Seriously, phasor analysis of circuits is almost no different from DC analysis. Resistors are still R, Capacitors are now 1/(jwC) and Inductors are jwL. So treating them all the same as resistors, you can do the same analysis as you did before. If you have a voltage v1 across the capacitor, the AC current flowing through the capacitor is just v/(1/jwC) (almost similiar to V/R). Chances are you're doing everything right and just have some small error or so. Think you can scan up your work to proofread?

Edit: Quirks? umm.... j*j = -1? 1/j = -j? lol... sorry, can't help there. If you use your TI-89 to calculate phase using arctan, you may run into problems. Like -1-j. That really has a phase of 135 degrees, and if you just plug it in your calculator as in arctan(-1/-1) you'll get 45.

 

[ManOnTheSide]

haha! good luck dude. circuit analysis sucks arse.

 

[OS]

I'd like to help but I feel like I forgot everything after I graduated. Which is sad cause I only graduated like two weeks ago.