How to find currents and voltages in circuits

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Homework Help Overview

The discussion revolves around analyzing a circuit with resistors in both series and parallel configurations. The original poster seeks to find the equivalent resistance, currents, and voltages in the circuit, which includes a battery and three resistors with specified values.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to describe the circuit layout and expresses uncertainty about how to begin calculating the equivalent resistance and the currents and voltages. Some participants suggest calculating the equivalent resistance of the parallel resistors first and then combining it with the series resistor. Others inquire about the original poster's understanding of determining currents and voltages from the equivalent resistance.

Discussion Status

Participants are exploring the circuit's configuration and discussing the calculations for equivalent resistance. Some guidance has been offered regarding the calculation of the equivalent resistance for the parallel resistors, but the original poster remains uncertain about the subsequent steps to find currents and voltages.

Contextual Notes

The original poster has expressed difficulty with the circuit's configuration and the calculations involved, indicating a need for clearer visual representation and further explanation of the concepts at play.

chase222
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I have to find the Requivalent and all of the currents and voltages in the circuit below.

l------------Resistor 1----l---------l
l l l
battery l l
l Resistor 2 Resistor 3
l l l
l l l
-----------------------------------l

My picture is not showing up right, so I'll try to describe it. The battery is on the left and the wire moves up to the right where resistor 1 is. The wire continues, but splits into two paths (making a parallel). The wire turns to the right, where resistor 2 is, but if you keep going straight and then turn right, that's where resistor 3 is.

they give us the following:
R1=40 ohms
R2=60 ohms
R3=60 ohms
Vtotal=120 V

I am not sure where to even start. I know V=IR, and I-V/R, but I don't know how to find the other numbers. I also know that in a series, current stays the same while voltage changes, while in parallel, current changes, while voltage stays the same.

I also know that for series, the Req= R1+R2, while in a parallel, 1/Req=1/R1+1/R2

I just can't figure out the numbers when you have a parallel in a series. Can you help me get started?
 
Last edited:
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The two resistors that are in parallel are equivilent to a resisitor with the resistance of R where (1/R)= (1/60)+(1/60) which would be 30 ohms and then that equivilent resistor is in series with the first resistor so don't you just add them together so the total resistance would be 70 ohms?
 
I agree with Yapper .. By your description, it sounds like R2 & R3 are in parallel, so 60ohm || 60ohm = 30 ohms. The 30ohms is then in series with R1. So Req = R1 + R2 || R3

Do you know how to determine all the currents and voltages in your circuit, from here?
 
No, I don't. Could you explain it to me?
 
Could you creat a drawing in paint, so the image would be easier to work with? That way, you might receive more help.
 

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