Find the Thevenin resistance for network with dependent current source

In summary, the student is trying to solve a problem that their professor has given them, but they are not sure how to approach it because of the dependent current source. They are looking for help finding V and I, as well as R(Th).
  • #1
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Homework Statement

http://imageshack.us/a/img15/7218/sg2prob11.jpg
Find the Thevenin resistance for the network(Sorry for the bad drawing, but that is a point like point / node A on the bottom where it's going out too and likely part of the load too, with a wire connected to the circuit, I'll see if I can draw it better when I get home)

Homework Equations



V = IR

KVL, KCL,

voltage division, current division

Thevenin procedures, etc

The Attempt at a Solution



I'm not sure how to approach this problem, because of that dependent current source (49i). Apparently you can't just silence the voltage source and then take the resistance from point a to the bottom point (which would've just been 96.7 ohms).

Any tips?
 
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  • #2


Where is the current i defined?
 
  • #3


I'm not too sure about that either, but it would probably have to do with the non-load in the circuit?


Or can you take that dependent current source as part of the load too? Or just cut it out of the wire (open-circuited) ?? (Where I guess the current i would then be in the rest of the circuit)
 
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  • #4


Apparently the dependent current source generates a current of 49 times i, where i is a current somewhere else in the network. i could be the current in either of the resistors, for example. You need to find out where i is.
 
  • #5


Once you figure out where the current for the dependent source is defined in the circuit the rest of the problem should be pretty straight forward.

To find find the Thevenin resistance looking into the terminals you must first find the open circuit voltage and the short circuit current.
 
  • #6


So is it possible to find an 'I' or is it impossible without an 'I' specifically given.

(My professor wrote up this problem and it's possible he forgot to put this on the problem and he's done it before)
 
  • #7


You can't solve the problem with knowing what current is represented by "i".
 
  • #8


He gave the answer to R(Th) though, would it be possible to solve for I then?
 
  • #9


What did he give? Did he also give Vth? It would probably be possible to work the problem with all possible locations for i and see which one gave the Rth you prof gave you.
 

Related to Find the Thevenin resistance for network with dependent current source

1. What is a Thevenin resistance?

A Thevenin resistance is the equivalent resistance of a circuit when viewed from two terminals. It is used to simplify complex circuits and make it easier to calculate voltage and current.

2. How do you find the Thevenin resistance for a network with a dependent current source?

To find the Thevenin resistance for a network with a dependent current source, you need to first calculate the open circuit voltage of the network. Then, you can use the formula RTh = VOC/ISC to find the Thevenin resistance, where VOC is the open circuit voltage and ISC is the short circuit current.

3. Can a dependent current source affect the Thevenin resistance of a network?

Yes, a dependent current source can affect the Thevenin resistance of a network. The value of the dependent current source can change, depending on the network it is connected to, which can alter the open circuit voltage and therefore the Thevenin resistance.

4. How does the Thevenin resistance affect the overall performance of a circuit?

The Thevenin resistance affects the overall performance of a circuit by determining the maximum amount of current that can flow through the circuit. A lower Thevenin resistance means that more current can flow, while a higher Thevenin resistance restricts the flow of current.

5. Can the Thevenin resistance be negative?

No, the Thevenin resistance cannot be negative. It is always a positive value, as it represents the equivalent resistance of a circuit. A negative value would not make sense in this context.

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