Solving for Req in a Series Circuit - Understanding Resistors and Voltage

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In summary, the resistors in the middle can be added to a total of 5 ohms. The total resistance including the middle branch is then 12.5 ohms, with the parallel combination of the two 5 ohm resistors adding to 2.5 ohms and the remaining 1.5 and 1 ohm resistors adding in series.
  • #1
J.live
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Homework Statement



Solve for Req



The Attempt at a Solution



The resistors in the middle can be added to total of 5 ohms. So then then 5v +5ohms = 10 ohms

Then they are all in series 1.5+10+ 1.5= 12.5? What I don't understand is what do i do with
Rx? or 12.5 is Req?

Here is the circuit:
 

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  • #2
hmm. just an fyi: i don't see any circuit beneath your promise for the circuit
 
  • #3
Sorry about that.
 
  • #4
you are correct that the middle branch can be replaced with 5 ohms. However, it does not add in series with the other 5 ohm resistor to its right. instead, they add in parallel. Then that parallel combination adds in series with the 1.5 and 1 ohm resistors.
 
  • #5


In a series circuit, the equivalent resistance (Req) is equal to the sum of all the individual resistances. In this case, we have three resistors: 1.5 ohms, 5 ohms, and 1.5 ohms. So, Req = 1.5 ohms + 5 ohms + 1.5 ohms = 8 ohms.

To understand this concept, imagine a water pipe with three sections of different widths. The total resistance to the flow of water would be equal to the sum of the individual resistances of each section. In the same way, the total resistance in a series circuit is equal to the sum of the individual resistances.

Now, to solve for Rx, we can use Ohm's Law, which states that voltage (V) is equal to current (I) multiplied by resistance (R). So, we can rearrange this equation to solve for resistance: R = V/I. In this case, we know the voltage (5V) and the total resistance (8 ohms), so we can solve for the current using Ohm's Law: I = V/R = 5V/8 ohms = 0.625 amps.

Now, to find the resistance of Rx, we can use Ohm's Law again: Rx = V/I = 5V/0.625 amps = 8 ohms.

So, the equivalent resistance (Req) in this series circuit is 8 ohms, and the resistance of Rx is also 8 ohms. This means that the total current (I) in the circuit is 0.625 amps, and the voltage drop across each resistor is proportional to its individual resistance. This understanding of series circuits is crucial for understanding more complex circuits and for designing and troubleshooting electrical systems.
 

Related to Solving for Req in a Series Circuit - Understanding Resistors and Voltage

1. What is "Req" in circuit solving?

"Req" stands for equivalent resistance and is a measure of the total resistance in a circuit. It is calculated by combining individual resistances in series and parallel circuits.

2. How do I calculate "Req" in a series circuit?

In a series circuit, the equivalent resistance is the sum of all individual resistances. This means that Req = R1 + R2 + R3 + ... where R1, R2, R3, etc. are the individual resistances.

3. How do I calculate "Req" in a parallel circuit?

In a parallel circuit, the equivalent resistance is calculated using the formula 1/Req = 1/R1 + 1/R2 + 1/R3 + ... This means that the reciprocal of Req is equal to the sum of the reciprocals of the individual resistances.

4. What is the purpose of solving for "Req" in a circuit?

Calculating the equivalent resistance in a circuit allows us to simplify the circuit and make it easier to analyze. It also helps us determine the amount of current that will flow through the circuit.

5. Can I use "Req" to calculate the total voltage or current in a circuit?

No, "Req" is only used to calculate the equivalent resistance in a circuit. To determine the total voltage or current, you would need to use Ohm's law or other circuit analysis methods.

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