Check my work please? Circuit analysis, resistors in parallel, help

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Homework Help Overview

The discussion revolves around circuit analysis, specifically focusing on resistors in parallel and the application of sign conventions in power calculations. Participants are examining the original poster's (OP) work on a circuit problem involving voltage sources and resistors.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The OP seeks verification of their calculations and expresses uncertainty regarding the sign convention for power in the circuit. Some participants discuss the implications of the passive sign convention and question how it applies to the power of the voltage sources and resistors.

Discussion Status

Participants are actively engaging with the OP's calculations, providing feedback on the correctness of the power values assigned to the sources and resistors. There is a mix of agreement and clarification regarding the signs of power, with some participants confirming the OP's findings while others offer corrections and alternative interpretations.

Contextual Notes

The OP mentions potential mistakes with sign conventions and seeks help in understanding which sources should be considered negative. There is also a reference to the passive convention and its application to the circuit analysis, indicating a focus on power relationships within the circuit.

nchin
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Can someone check my work for me please? I'm pretty sure i made a mistake with the sign convention but I'm not sure which sources are supposed to be negative. help!

Problem:
http://imageshack.us/a/img201/339/circuitzz.png

My solution:
http://imageshack.us/a/img191/8049/circuitz.png

The top half is me solving the left side the circuit and the bottom half is the right side of the circuit.
 
Last edited by a moderator:
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The basic calculations/magnitude look fine to me. However the passive convention says that the power of the sources would be negative. So for example the power of the 60V source is -0.6W.

Examples..
http://circuits.solved-problems.com/456/problem-1-15-power-independent-sources/
 
Last edited by a moderator:


so if the power of the 60v source is -0.6, does that mean the power in resistor 1 is -0.1 and the power in resisor 2 is -0.5? since power supplied = power dissipated?? (-0.6 = -0.1 + (-0.5))?
 


ok nvm i figured it out,, but am i solving r3 and r4 correctly?
 


nchin said:
so if the power of the 60v source is -0.6, does that mean the power in resistor 1 is -0.1 and the power in resisor 2 is -0.5? since power supplied = power dissipated?? (-0.6 = -0.1 + (-0.5))?

No the power dissipated in the resistors is +ve. You write something like..

Power in source + Power in load = 0

-0.6 + 0.1 + 0.5 = 0
 


I threw away the scrap paper I used yesterday but yes I got the same power disipation as you for R3 and 4.
 

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