Voltage drop and current for each resistor

In summary, Fallen186 asks for help with a homework problem and provides a helpful summary of the content.
  • #1
alan1592
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Homework Statement


heres a picture of the problem. Please don't give me the answer just tell me what are the steps to complete it. thanks.

http://i307.photobucket.com/albums/nn296/alan1592/download-1.jpg

Homework Equations



V=IR

The Attempt at a Solution



1/6+1/3=2 Ohms
 
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  • #2
Ok, so you now have two resistors in the circuit- you can calculate the voltage drop across each resistor and, using Ohm's law, the current. You need to be a little more specific with what you're looking for so you can get more help.
 
  • #3
Im looking to find those items. The voltage drop and the current. I don't know how.
 
  • #4
Since there is one indepedent voltage source of 20 Volts that means the voltage drop across all the resistors should equal 20V.

I would have made this look nice but the LaTex Isn't working.

First Combine the Resistors in Parrallel:
1/R =(1/R_1)+(1/R_2)+...(1/R_N)
1/R = (1/6 Ohm) +(1/3 Ohm)
1/R = (1/6 Ohm) + (2/6 Ohm)
1/R = (3/6 Ohm) = (1/2 Ohm)

1/(1/2 Ohm) = R = 2 Ohm

So now you have
---||----^^^^---^^^^-|
|___________________|

Sorry for the bad drawing
( --||-- = voltage source, ^^^^ = resistor)


Now combine the resistors in series
R= R_1 +R_2+...R_N
R= 3 Ohm + 2 Ohm
R = 5 Ohm

So now you have

---||---^^^^--|
|____________|

Using V = IR you can solve for the current:
V=IR
(20 Volts) = I * (5 Ohm)
I = 4 Amperes

Now split the circuit back up so that it is 2 resistor in series.
Resistors in series have the same current
---||----^^^^---^^^^-|
|___________________|

So for the first resistor (3 Ohm resistor)
V = IR
I = 4 Ampere
R = 3 Ohms

V = (4 Ampere)(3 Ohm)
V= 12 Volts
Voltage on the 3 Ohm resistor directly right of the independent voltage source is 12 volts


Now for the second resistor (2 Ohm Resistor)
V = IR
I = 4 Ampere
R = 2 Ohms

V = (4 Ampere)(2 Ohms)
V = 8 Volts
Voltage on the 2 Ohm resistor directly right of the 3 Ohm resistor is 8 volts.

Split it up so you are back with the circuit you were first with.
---||---^^^^-.----^^^^--|
|___________|----^^^^--|

Resistors in parrallel have the same voltage so:
6 Ohm Resistor in Parrallel:

V=IR
(8 volts) = I * (6 Ohm)
I = (4/3) Amperes

3 Ohm Resistor In parrallel:

V= IR
(8 Volts) = I * ( 3 Ohm)

I = (8/3) Ampere

So,
Resistor 1:
Resistor(R)= 3 Ohm
Voltage Drop(V) = 12 Volts
Current(i) = 4 Amperes

Resistor 2:
Resistor(R) = 6 Ohm
Voltage Drop(V) = 8 Volts
Current(i) = (4/3) Ampere

Resistor 3:
Resistor(R) = 3 Ohm
Voltage Drop(V) = 8 Volts
Current(i) = (8/3) Ampere
 
  • #5
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  • #6
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  • #7
Cheesus128 said:
Whats the point of that rule?
So the members here don't do your homework
 
  • #8
Fronzbot said:
So the members here don't do your homework

Hahahaha that made me smile
Oh well every forum has its own rule.
But still its not like he is posting his whole paper or HW here, he is only posting one question so wouldn't that be something else?
I mean mostly you can only find how something works by knowing the answer and the exact way of getting there.
Hence you need the full explanation?
 
  • #9
Yeah he was very helpful to me too. I deff learned how to do the problem and that's what i wanted. Thanks man!
 

FAQ: Voltage drop and current for each resistor

1. What is voltage drop?

Voltage drop is the decrease in voltage that occurs when current flows through a component or circuit. It is measured in volts (V) and is caused by the resistance of the component or circuit.

2. How is voltage drop calculated?

Voltage drop can be calculated using Ohm's Law, which states that voltage drop (V) equals the current (I) multiplied by the resistance (R) of the component or circuit. It can also be calculated using Kirchhoff's Voltage Law, which states that the sum of the voltage drops in a closed loop circuit is equal to the sum of the voltage sources.

3. What is current?

Current is the flow of electric charge through a conductor, such as a wire or circuit. It is measured in amps (A) and is the rate at which electric charges move through a given point in a circuit.

4. How is current affected by resistance?

According to Ohm's Law, current is inversely proportional to resistance, meaning that an increase in resistance will result in a decrease in current, and vice versa. This is because a higher resistance will impede the flow of electric charges, reducing the current.

5. How does voltage drop affect the overall circuit?

Voltage drop can affect the overall circuit by reducing the amount of voltage available for other components in the circuit. This can lead to a decrease in performance or malfunctioning of the circuit. It is important to consider voltage drop when designing a circuit to ensure proper functioning.

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