Friday, September 7, 2012

NORTON'S THEOREM (Solved problems)


Solved problems on Norton’s theorem


Q1) Find the Norton’s equivalent circuit across A-B terminals for the circuit shown in figure 14.1



Answer:


First we remove the 10Ω resistor and short circuit the terminals A&B. see figure 14.2



The current flowing through the short circuited terminals is called the Norton’s curren IN.

To find the IN we apply nodal equation for point C

(V – 30)/5 + V/10 + V/3 = 0

V = 180/19

Ohms law to 3Ω resistance

I = V/R

IN = (180/19) / 3

IN = 60/19

This is the Norton’s current.

Now we are about to find the Norton’s resistance. Note that this is equal to the thevenin’s resistance also.
See figure 14.3


RN = (10//5) + 3

RN = 19/3Ω



Q2) Find the Norton’s equivalent circuit across A-B terminals for the circuit shown in figure 14.4






Answer:

First we short circuit the two terminals A&B and calculate the current flowing
See figure 14.5

When we short circuit A-B terminals it results in shorting out 12Ω resistor as shown in figure 14.6

Now we can simply find the current IN by applying Ohms law to 4Ω resistor,

I  = V/R

IN = 24/4

IN = 6A

Then we find the RN . See figure 14.7



RN = 12//4

RN = 3Ω



Q3) Using Norton’s theorem calculates the current flowing through 12Ω resistor. You may refer figure 14.8





Wait for my next post to see the solution. Till then, try this yourself. It is very similar to Q1.


32 comments:

  1. why the Q1 answer norton's current are not divided?..i mean y 180 can't divide in 19?

    ReplyDelete
  2. I'm sorry Can you please clarify your problem again?

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  3. how 2 solve the norton equation wchich ha dependent source

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  4. I am clueless about this statement. First we remove the 10Ω resistance and short circuit the terminals A&B. see figure 14.2. Why isn't 12ohm resistor there?

    ReplyDelete
    Replies
    1. I am just mentioning the 10 ohm resistor which is in between the points A&B

      Delete
  5. This comment has been removed by a blog administrator.

    ReplyDelete
  6. answers of the questions is;
    In=4amp & Rn=6ohm
    is this right?

    ReplyDelete
    Replies
    1. http://eefundamentals.blogspot.com/2012/09/nortons-theorem-solved-problems2.html

      check it over there. thank you for viewing

      Delete
  7. i got current through 12 ohm resistor is 0.8866 ohm.Is it correct?

    ReplyDelete
    Replies
    1. http://eefundamentals.blogspot.com/2012/09/nortons-theorem-solved-problems2.html

      refer the link

      Delete
  8. no current will flow there, current will choose flow where there is no resistance

    ReplyDelete
  9. ?how 12ohm get shorted? plsexplain wid reason

    ReplyDelete
    Replies
    1. it's simply like this, when there is a highway to travel, no one uses the narrow road. electrons do so....

      Delete
  10. How 12 ohm get shorted? Plz say again

    ReplyDelete
  11. How 12 ohm get shorted? Plz say again

    ReplyDelete
    Replies
    1. Okay, this is how it happens, if you connect a resistor parallely with a conductor (say 12ohm resistor and 0 ohm resistor) current never flows through the resistor. it always choose the conductor. that is the meaning of "no current will flow in 12 ohms resistor as it is short circuited".
      this is a rule you must apply on wherever you find a resistor is parallel connected with a conductor (or 0 ohm resistor). Hope you understood.
      if still you have problems, please let me know.

      Delete
  12. How to solve the problem if load resistor is in the middle of the circuit?

    ReplyDelete
  13. IN Q1 fig 14.3 why 3 ohm resistance is consider ,even it is short

    ReplyDelete
  14. In= 4A, Rn= 6ohm, Current across the load resistor (i.e. Across 12ohm resistor) Il=1.33A, Voltage across 12 ohm = 16V.

    ReplyDelete
  15. Last one, I= 1.24V and R=5.4ohms

    ReplyDelete
  16. I found the answer of Q3 as follows
    IL=1.33 A

    ReplyDelete
  17. I found the answer of Q3 as follows
    IN=4A
    IL=1.33 A

    ReplyDelete
  18. There is something wrong in the Q1.. We v and In.. In will be 90/19

    ReplyDelete
    Replies
    1. No. nothing is wrong with the question rishab. Please upload your work sheet. I will guide you and show u where u did wrong.
      Thank you.

      Delete

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