Question

Electrical Circuit Questions! Please Help me!!!

Answer 1

anyone know the steps?

Answer 2

Do you want only answer or you want me to explain??

Answer 3

Oh I didn't see you asked for steps. First find the equivalent resistance. You should get 7 ohm

Answer 4

Then find the current, V = i R
36 = i * 7
i = 36/7 amperes

Answer 5

This current flows through the 5 ohm resistor and then splits into two half's, so the current through 3 ohm resistor is 36/14 amperes

Answer 6

Vth is the potential difference across 3 ohm resistor ( asked across 3 ohm resistor) = i* R

Vth = 36/14 * 3

Vth = 54/7

Answer 7

Are you der??

Answer 8

My understanding is that the Thevenin voltage is the open circuit voltage with the 3 ohm load resistor disconnected. This is given by:
\[V _{th}=36\times\frac{4}{9}=16\ volts\]

Answer 9

@kropot72 No that's wrong

Answer 10

No, it's correct. Refer to the information here:
http://en.wikipedia.org/wiki/Th%C3%A9venin%27s_theorem

Answer 11

@adunb8 I need to go. If you have any doubts in my solution I can help!!

Answer 12

@kropot72 read it properly. From the perspective of 3 ohm load resistor means if you are adding an external circuit at that point, how much voltage is it going to supply(Vth)

Answer 13

I did read it properly. The 3 ohm resistor is a load.
"........from the perspective of the 3 ohm resistor...." means looking back from where the load is connected.

Answer 14

If Thevenin's theorem is used, it is necessary to calculate the Thevenin voltage with the load terminals open circuited.

Answer 15

Whatever the explanation in wiki is a bit confusing but I'm sure that my solution is right. @adunb8 check my answer if its right use my solution else ignore it!!

Answer 16

It seems the following instruction below the question tells you the correct method:
"Find the open circuit voltage with the 3 Ohm resistor disconnected."

Answer 17

oh thank you guys for the replies!

Answer 18

@kropot72 May be you are right. I'm not exactly sure about the sentence from the perspective of 3 ohm load resistor.
If they want to add an external circuit at the terminals of 3 ohm resistor then my solution is right!!
If they want to find the Vth and Rth for the remaining circuit then you are right!!

Answer 19

@kropot72 yeah! the answer is 16 !

Answer 20

You're welcome :)

Answer 21

so the Rth would be adding total resistors?

Answer 22

To find Rth short circuit the Voltage source and find the equivalent resistance

Answer 23

Just calculate the resistance between A and B. The 36 V generator is replaced by a short circuit.