Thevenin Equivalent with a dependent source

Thread Starter

RedDead

Joined Dec 12, 2010
14
Find the Thevenin Equivalent circuit between A and B
the circuit is in the attachments...
i don't know how to start
and what is the difference if A and B were for e.g after the 6V source?

thanks :D
 

Attachments

Jony130

Joined Feb 17, 2009
5,487
To find Thevenin's equivalent at terminals a & b you need to find

1. The open circuit voltage Vab = Vth.
2. The current flowing from a to b when a & b are shorted together.
3. Hence find Rth = Vab(open circuit)/Iab(short circuit)
 

Thread Starter

RedDead

Joined Dec 12, 2010
14
To find Thevenin's equivalent at terminals a & b you need to find

1. The open circuit voltage Vab = Vth.
2. The current flowing from a to b when a & b are shorted together.
3. Hence find Rth = Vab(open circuit)/Iab(short circuit)
i know that, but i am confused about how to start because there is a dependent source.
how can i find Vx?
 

Jony130

Joined Feb 17, 2009
5,487
Well first you need to find Vth voltages
So diagram look like this



Vth = - V1 * R2/ (R2+R3) = -3.2V

And now we need to find Isc



So I write nodal equation

(Va - (-8V) )/3Ω = (0V-Va)/1Ω + ( (-5•Va) - Va )/2Ω

So the only think you need to do, is to find voltage at Va node.
 

Jony130

Joined Feb 17, 2009
5,487
Well I remove this resistor becaues it is connect parallel to the voltage source.
So this resistor has no effect on Va voltages.
 
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