Find the equivalent resistance seen by the source

In summary: But then I saw that Kirchoff's and Ohm's laws were being used, and I got it. Thanks for clarifying it for me.
  • #1
scanferr
3
0

Homework Statement



Find:

a) the equivalent resistor seen by the source;
b) value of i0;
c) value of v;
d) value of v0.

http://img823.imageshack.us/img823/4406/dasso.jpg


Homework Equations



Kirchoff's laws and Ohm's laws

The Attempt at a Solution



To solve b,c,d I need to get a right which I didn't. I got 6Ω for the equivalent resistor and the right answer is 8Ω. I don't understand why!
Isn't the circuit made of those 36Ω and 44Ω in series and the 40Ω,10Ω,30Ω in series and the parallel of those with the rest? I don't get why I got it wrong.

Can you people help me?
 
Last edited by a moderator:
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  • #2
scanferr said:

Homework Statement



Find:

a) the equivalent resistor seen by the source;
b) value of i0;
c) value of v;
d) value of v0.

http://img823.imageshack.us/img823/4406/dasso.jpg

Homework Equations



Kirchoff's laws and Ohm's laws

The Attempt at a Solution



To solve b,c,d I need to get a right which I didn't. I got 6Ω for the equivalent resistor and the right answer is 8Ω. I don't understand why!
Isn't the circuit made of those 36Ω and 44Ω in series and the 40Ω,10Ω,30Ω in series and the parallel of those with the rest? I don't get why I got it wrong.

Can you people help me?
Hello scanferr. Welcome to PF !

[STRIKE]I also get 8Ω for the equivalent resistance.[/STRIKE]

Show how you got your answer.

Added in Edit:

Actually, I also get 6Ω .

I don't know why I initially wrote 8Ω .
 
Last edited by a moderator:
  • #3
I got 6 ohm as my answer !
 
  • #4
6 ohms here, too. How can we all be using the same buggy calculator? :wink:
 
  • #5
I get 6 ohms too. 8 ohms is just wrong. It happens.

Anyway, you would then calculate the voltage between the top and bottom supply rails and calculate the currents through the parallel resistors and networks.

V = I * R. I = 8 amps. R = 6 ohms.
 
  • #6
Thanks guys!

It seems the solution is wrong then. It happens yes, and I was kinda confused because I didn't know how 8ohms could be right!
 

1. What is equivalent resistance?

Equivalent resistance refers to the total resistance that a power source sees when connected to a circuit. It takes into account the individual resistances of all components in the circuit and simplifies it into one single resistance value.

2. Why is it important to find the equivalent resistance?

Finding the equivalent resistance is important because it allows us to understand and analyze the behavior of a circuit as a whole. It helps us determine the amount of current that will flow through the circuit and the amount of power that will be dissipated.

3. How do you calculate the equivalent resistance of a series circuit?

In a series circuit, the equivalent resistance is simply the sum of all individual resistances. This can be calculated by adding all the resistance values together.

4. How do you calculate the equivalent resistance of a parallel circuit?

In a parallel circuit, the equivalent resistance is calculated using the formula 1/Req = 1/R1 + 1/R2 + ... + 1/Rn, where Req is the equivalent resistance and R1, R2, etc. are the individual resistances. This formula takes into account the fact that the total current in a parallel circuit is divided among the different branches.

5. What is the effect of adding resistors in series or in parallel on the equivalent resistance?

In a series circuit, adding resistors increases the equivalent resistance, as the total resistance is the sum of all individual resistances. In a parallel circuit, adding resistors decreases the equivalent resistance, as more branches are created for the current to flow through, reducing the overall resistance of the circuit.

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