Question

I have another circuit to analyze here. help please.

Answer 1

perhaps u should try another forum.
there's an engineering forum!

Answer 2

Node V1 :

15 = V1(1/1 + 1/2) - Vx(1/2)

Answer 3

if you see there is a resistance in serie with a current source between node V2 and ground

Answer 4

right?

Answer 5

yes

Answer 6

then you can remove that resistance of 2 ohm , right?

Answer 7

yes. !

Answer 8

ok then at node V2

-15 - Vx/9 = V2 (1/1) - Vx (1/1)

Answer 9

and node Vx

0 = Vx(1/2 + 1/1 + 1/3) - V1 (1/2) - V2 (1/1)

Answer 10

then you have 3 equations and 3 variables (V1,V2,Vx)

Answer 11

do you understand what i did? ^^

Answer 12

PS I'm not very tidy

Answer 13

it's alright, i'll try to do as u said. thank you so much! :D

Answer 14

i found Vx = 12.857V

Answer 15

question. why not V1-Vx(1/2)-V2-Vx(1/1) ? at node Vx?

Answer 16

if you see in all equations of node i folow these steps :

at node VA

1.) the sum of all currents , in current at node (+) out current (-)
2.) it is equal to :
sum of:
- this node multiplied by admittances(inverse of resistors) wich come to that node
- other nodes that are connected to this node for one (or more) resistances multiplied for
the admittance between then but with sign -
- so on for all resistances

Answer 17

so for node V1there
incoming current : +15

this node is V1 so (there are 2 resistances [1 and 2 ohms] connected to this node)
V1*(1/1 + 1/2)
remember there are 2 resistances connected to V1 that is 1 that connect to V1 with "ground" , if is ground , i won't take that node because it is 0, and resistance of 2 ohms connect to node V1 with Vx so
Vx*(1/2) but with negativ sign!

then i will have


15 = V1*(1/1 + 1/2 ) - Vx*(1/2)

Answer 18

if you do the same for node Vx you will get this equation

0 = Vx(1/2 + 1/1 + 1/3) - V1 (1/2) - V2 (1/1)

Answer 19

ok, thank you very much. i get it now! thank you for explaining it to me. :)

Answer 20

tell me the solution that you find ;)

Answer 21

i got 0 for Vx.

Answer 22

-5 for V1 and - 1.5 for V2

Answer 23

I found
V1= 5.714
V2 = -26.428
Vx = -12.85

Answer 24

i used cramer's to solve for the unknowns, why can't i get it?

Answer 25

what are your matrix?