# Parallel voltage sources circuit

by Femme_physics
Tags: circuit, parallel, sources, voltage
PF Gold
P: 2,551
 I intended to ask for the power dissipation in the 4 ohm resistor that is between A and B.
Easy peasy!

P2 = 2 x 5.211^2 = 54.31 [W]

 I give you the smurfs. All of them are yours, you *evil* you!
Muwahhaahahhah!!!!

 Btw, the total power is the sum of the powers dissipated in each of the 3 resistors.
You mean
Pt = Power dissipated in resistor 1 +Power dissipated in resistor 2 + Power dissipated in resistor 3?

In which case, I was aware of that!

And I did get the correct result, yes?
HW Helper
P: 6,189
 Quote by Femme_physics Easy peasy! P2 = 2 x 5.211^2 = 54.31 [W] Muwahhaahahhah!!!! You mean Pt = Power dissipated in resistor 1 +Power dissipated in resistor 2 + Power dissipated in resistor 3? In which case, I was aware of that! And I did get the correct result, yes?
Let me see...

We got a total power of 258.65 W.
Subtract 199.46 W from your previous result.
Subtract another 54.31 W that you just got.

That leaves.... 4.88 W for the 4 ohm resistor between A and B.
Yes! That's it! You got it!
 PF Gold P: 2,551 w00000000000000000t You rock! I'll probably do the other one tomorrow^^ You're incredible, ILS!!! This is pretty fun for me, I don't know about you You're a life saver. I'm pretty stressed about term B in electronics, it's my last chance at "redemption" for this course.
 HW Helper P: 6,189 Neh, this is no fun for me. ;)
 Sci Advisor HW Helper P: 1,326 You did a nice job !! (!עבודה טובה) There are typically several approaches to the same question. Some take fewer steps than others. Here is the method I was suggesting you try. (It may help save you some time on an exam) You found currents for the initial question to be I1=1.105, I2=5.211A and I3= I0 = 6.316A Next was find VAB and PAB (with respect to R1). V= IR ; VAB = I1R1 = (1.105)(4) = 4.42V P = IV; PAB = I1VAB = (1.105)(4.42) = 4.88W
 PF Gold P: 2,551 Duly noted Quabache Next time I will certainly be wiser I will try me hands on another exercise this morning (it's 4:30 AM here. I'm an early riser!)
PF Gold
P: 2,551
 Quote by I like Serena And here's a second one. Perhaps you can start a separate thread for this problem? For the circuit shown below, determine the voltage for each of the resistors and label the values on the diagram.
That was pretty easy. I didn't find P for each just for lack of patience. I know I know it!

 HW Helper P: 6,189 Hmm, it seems you've been progressing..... But wait! You did not get all the smurfs! Which smurf did you miss?
 PF Gold P: 2,551 Yea I know finding the P in each of them...but com'on you just apply a formula it's soooooooooooooo easy! Lemme skip that pretty please?
PF Gold
P: 2,551
First question--

How come they get to pick for me the direction of I? Shouldn't I be the one determining it?
 HW Helper P: 6,189 Not that. You made a mistake. Perhaps I should have said that you dropped a smurf?
HW Helper
P: 6,189
 Quote by Femme_physics First question-- How come they get to pick for me the direction of I? Shouldn't I be the one determining it?
Well....

You did not mark the directions of the currents (and as a consequence you made a mistake with it).
So I thought I'd better mark them for you!

(Just kidding, I just picked the first exercise that fitted your description. )

The real reason would be that the people who made the exercise would want the same answer from all students, so it's easier for them to check the answers. This means naming the currents and preselecting the directions.
PF Gold
P: 2,551
 Quote by I like Serena Not that. You made a mistake. Perhaps I should have said that you dropped a smurf?
More like a typo! I've accidentally linked the wrong file

PF Gold
P: 2,551
 Quote by I like Serena Well.... Look at the drawing in your first post in this thread. You did not mark the directions of the currents (and as a consequence you made a mistake with it). So I thought I'd better mark them for you! (Just kidding, I just picked the first exercise that fitted your description. ) The real reason would be that the people who made the exercise would want the same answer from all students, so it's easier for them to check the answers. This means naming the currents and preselecting the directions.
Interesting. So you get different answers if you pick different direction for I? I didn't know that!
HW Helper
P: 6,189
 Quote by Femme_physics More like a typo! I've accidentally linked the wrong file
Yep! You found the smurf! :)

 Quote by Femme_physics Interesting. So you get different answers if you pick different direction for I? I didn't know that!
If you pick the direction of a force in mechanics in the other direction, don't you get a different answer too?
PF Gold
P: 2,551
 Yep! You found the smurf! :)
No, no! I already had the smurf, I just mispointed on him! Like, it's totally not fair that you think I had to correct myself I already fixed that typo!!! grrr!!! I wrote the answer at the second line instead of doing the equal sign and stuff.....ah nevermind you wouldn't ever believe me anyway!! *storms off*

*comes back*

Oh right there's an exercise to solve. But if I didn't have....if I didn't....I'd so storm off right now!

As if!

 If you pick the direction of a force in mechanics in the other direction, don't you get a different answer too?
You get the same value, just with a minus or plus
 PF Gold P: 2,551 Hmm.... would it be reasonable to ask an easier parallel voltage sources problem before I try this one? I really want more practice on basic circuits with parallel voltages first...unless you think it would be redundant to me now? Whatever you tell me
 PF Gold P: 2,551 I've really decided it's too complex since we're not gonna have something THAT difficult on the test!

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