Circuit help (parallel and series together)

In summary, the 50V independent voltage source supplies power to three resistors in a circuit. For each resistor, find the voltage drop and current.
  • #1
sloan13
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0

Homework Statement


A 50V independent voltage source supplies power to three resistors in the circuit shown below. For each resistor find the voltage drop and current.

Circuit Diagram:
https://webwork2.uncc.edu/webwork2_files/tmp/Fall2014-Engr1201-Common/img/f65baf2e-12f5-3b7e-898f-18c0cd5a2145___71184e03-0c3d-3804-97e6-b93ed961be0a.gif

RA = 55 Ω, RB = 310 Ω, and RC = 24 Ω.

Vdrop across RA = ____V
Vdrop across RB = ____V
Vdrop across RC = ____V

Current through RA = ____A
Current through RB = ____A
Current through RC = ____A


Homework Equations


V = RI

V = Voltage
R = Resistance
I = Current

____________________________

R = r1 + r2 + r3... (series)
1/R = 1/r1 + 1/r2 + 1/r3... (parallel)

____________________________


The Attempt at a Solution


I have tried solving this by solving the voltage and current at each individual resistor and munipulating formulas. I haven't really gotten anywhere. We haven't been over this stuff in class and the handout doesn't cover this, but they refused to change the due date.

I am so lost.
 
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  • #2
sloan13 said:

Homework Statement


A 50V independent voltage source supplies power to three resistors in the circuit shown below. For each resistor find the voltage drop and current.

Circuit Diagram:
https://webwork2.uncc.edu/webwork2_files/tmp/Fall2014-Engr1201-Common/img/f65baf2e-12f5-3b7e-898f-18c0cd5a2145___71184e03-0c3d-3804-97e6-b93ed961be0a.gif

RA = 55 Ω, RB = 310 Ω, and RC = 24 Ω.

Vdrop across RA = ____V
Vdrop across RB = ____V
Vdrop across RC = ____V

Current through RA = ____A
Current through RB = ____A
Current through RC = ____A


Homework Equations


V = RI

V = Voltage
R = Resistance
I = Current

____________________________

R = r1 + r2 + r3... (series)
1/R = 1/r1 + 1/r2 + 1/r3... (parallel)

____________________________


The Attempt at a Solution


I have tried solving this by solving the voltage and current at each individual resistor and munipulating formulas. I haven't really gotten anywhere. We haven't been over this stuff in class and the handout doesn't cover this, but they refused to change the due date.

I am so lost.

Please show us your work so far. It's pretty hard to help you without seeing how you are approaching the problem.
 
Last edited by a moderator:
  • #3
Well, I have tried applying Kirchoff's Laws and tried to find the currents of the first two resistors, but I don't think I can without knowing all but one of them.

50V - IR1 - IR2 - IR3 = 0
50V - 55I1 - 310I2 - (24)(.707090275) = 0

I found the third current by taking the voltage/overall resistance. (The third current and voltage drop and they were correct)

I don't think I can calculate the voltage drop without knowing the current or vice versa.
 
  • #4
Oh and I also tried getting the percentage of resistance of both sides of the parallel resistors and tried applying it to the current of both respectively.
 
  • #5
Why not find the total current coming from the voltage supply? (simplify the resistor network) then you know the total current through Rc.

With the current through Rc, you can find the voltage drop across Rc. Then 50-Rc voltage drop is the voltage across both Ra and Rc. So you can find the current through each of those as well.

Does anything here not make sense?
 
  • #6
Well I got Rc, but basically you are saying that I can find Ra voltage drop by:

50V = Ra - (Rc voltage drop)?
 
  • #7
no Ra = 50- Rc voltage drop

50V would actually be the sum, that is: 50=(Ravoltage drop)+(Rcvoltage drop)
 
  • #8
you know all the resistances so that's not an issue, the first trick is to find the total current from the source.
 
  • #9
find an equivalent circuit resistance (the resistance seen by the source)

That is, Rc in series with (Ra and Rb in parallel)

then use ohms law to find total current. total current = 50v/total resistance
 
  • #10
I got it! Thanks guys!
 
  • #11
The issue for me was that I thought that 50V was the sum of the voltage of the entire circuit, as in Ra V + Rb V + Rc V. Again, thank you!
 
  • #12
ahh, I see.

Most welcome
 
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Related to Circuit help (parallel and series together)

1. What is the difference between a parallel and series circuit?

In a parallel circuit, the components are connected in such a way that there are multiple paths for the current to flow. In a series circuit, the components are connected in a single loop, so the current flows through each component in sequence.

2. How do I calculate the total resistance in a parallel and series circuit?

In a parallel circuit, the total resistance is calculated by adding the reciprocals of each individual resistance and then taking the reciprocal of the sum. In a series circuit, the total resistance is simply the sum of all individual resistances.

3. Can I mix parallel and series components in the same circuit?

Yes, it is possible to have parallel and series components in the same circuit. This is known as a combination circuit, and it is commonly used in electronic devices.

4. What happens if one component in a series circuit fails?

If one component in a series circuit fails, the entire circuit will be disrupted and the current will stop flowing. This is because in a series circuit, the current must flow through each component in order to reach the end.

5. How can I improve the performance of a parallel and series circuit?

To improve the performance of a parallel circuit, you can add more branches to the circuit, which will increase the current flow and decrease the overall resistance. To improve the performance of a series circuit, you can decrease the number of components in the loop, which will reduce the overall resistance and increase the current flow.

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