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thevenin again

Discussion in 'Homework Help' started by stupid, Nov 29, 2009.

1. stupid Thread Starter Active Member

Oct 18, 2009
81
0
hi,
attached are my working. Pls verify if my answer were correct.

first convert norton part to thevenin.
thus the current-ctrl voltage source is 70i & 20Ω in series with the circuit.

to compute V$_{ab}$,
-10 + 10i + 20i - 70i=0
i= -0.25A

i(20)-(70i)= -5+17.5= 12.5V =V$_{ab}$

next to compute I$_{sc}$
short the ab terminal,
I$_{sc}$= i - 3.5i
v=0,
(-10+v)/10 = -i
i= 1

thus, I$_{sc}$= 1 - 3.5 = -2.5A

hence R$_{th}$= 12.5/-2.5 = -5Ω

i m wondering if i got them right.

• thevenin2.JPG
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Last edited: Nov 29, 2009
2. hgmjr Retired Moderator

Jan 28, 2005
9,029
219
It looks as though you forgot to attach your file?

hgmjr

3. stupid Thread Starter Active Member

Oct 18, 2009
81
0
i did..pls check again.
thanks

4. nirvanaguy New Member

Oct 3, 2009
15
0
To my knowledge you can't have negative resistance.. so maybe your current shoudlnt be negative because I'm pretty sure you got your voltage correctly

5. Pinky Ringz New Member

Oct 4, 2009
6
0
remove the load, parallel the resistors until you get a simple series cct, reinsert the load and then calculate....no?

6. stupid Thread Starter Active Member

Oct 18, 2009
81
0
is the shorted cct current-ctrl current source a supermesh element?
i m lost at this.

regards,