# What should I do in this situation ? I have R_N <-Norton resistance and it's equal infinite

#### Xenon02

Joined Feb 24, 2021
489
Hello !

I've got a question.
When I have R_N <-Norton resistance and it's equal infinite --> Rn = infinite. Then I can't change Norton into Thevenin ? I mean here J_N into E_TH ?
If I had R_N = 0 can I also change J_N into E_TH ?

Thank you !

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#### MrSalts

Joined Apr 2, 2020
2,767
You could come up with a better title.

#### crutschow

Joined Mar 14, 2008
33,365
To change between a Norton and Thevenin equivalent circuit you also need the equivalent impedance of the rest of the circuit.
You can't convert an ideal current source into an ideal voltage source by itself.

#### MrAl

Joined Jun 17, 2014
10,920
Hello !

I've got a question.
When I have R_N <-Norton resistance and it's equal infinite --> Rn = infinite. Then I can't change Norton into Thevenin ? I mean here J_N into E_TH ?
If I had R_N = 0 can I also change J_N into E_TH ?

Thank you !
You should really post the circuit.

If you have an infinite resistance across an ideal current source the voltage is infinite.
If you have a zero resistance across an ideal voltage source the current is infinite.

Either of these may be ok in theory, but in practice there would be some limitation such as some series and/or parallel resistances for each type of source.

If you have zero resistance across a current source the voltage is zero.
If you have an infinite resistance in series with a voltage source the current is zero.

#### MrSalts

Joined Apr 2, 2020
2,767
You should really post the circuit.

If you have an infinite resistance across an ideal current source the voltage is infinite.
If you have a zero resistance across an ideal voltage source the current is infinite.

Either of these may be ok in theory, but in practice there would be some limitation such as some series and/or parallel resistances.
A fixed current though an infinite resistance is infinite power - a super hero. A god.
Now, would he have more power if the fixed current is increased?

#### MrAl

Joined Jun 17, 2014
10,920
A fixed current though an infinite resistance is infinite power - a super hero. A god.
Now, would he have more power if the fixed current is increased?
Hello,

Apparently you did not understand the difference between theory and practice. In theory you can have infinite quantities, in practice you cant, but i already indicated that in the previous post.

#### MrSalts

Joined Apr 2, 2020
2,767
Hello,

Apparently you did not understand the difference between theory and practice. In theory you can have infinite quantities, in practice you cant, but i already indicated that in the previous post.

#### MrAl

Joined Jun 17, 2014
10,920
You dont seem to understand what you read sorry.
Everything i stated before this is hard core facts. If you dont understand, you have to ask somebody or read a book.

Your example was a practical one, while my reply before had BOTH practical and theoretical parts, with the statements they went with. Two were theoretical, two were more practical.

If you want to discuss this further we should talk in PM's and not muddy up this thread. Thanks in advance for your anticipated cooperation.

#### crutschow

Joined Mar 14, 2008
33,365
So it is impossible to have Norton with Rn = 0?
Not impossible, but it would be of no practical use.
The Norton source would look like a short-circuit, with zero output voltage.
Practical equivalent sources need some finite impedance (not zero or infinite).

#### Xenon02

Joined Feb 24, 2021
489
Not impossible, but it would be of no practical use.
The Norton source would look like a short-circuit, with zero output voltage.
Practical equivalent sources need some finite impedance (not zero or infinite).
Maybe you are right but if I want to have Thevenince Voltage source from Norton source with RN = 0 then RT = 0 and ET= Jn*RT and we have ET = 0. Which is not logika because for Norton source the additional resistor R will have a Voltage equal UR= Jn*R.
But for ET it implicates that resistor R have no Voltage.Sorry for my lack of vocabulary some of my sentences May Sound stupid. But I believe you can Understand something out of it #### crutschow

Joined Mar 14, 2008
33,365
but if I want to have Thevenince Voltage source from Norton source with RN = 0
Why?
What don't you understand about that being of no practical use?

#### Xenon02

Joined Feb 24, 2021
489
I mean I know it is not practical but in the same time it is a bit conflicting as I mentioned before if I want to change Et to Jn.

#### crutschow

Joined Mar 14, 2008
33,365
I mean I know it is not practical but in the same time it is a bit conflicting as I mentioned before if I want to change Et to Jn.
The conversion procedure works expect for the pathological cases of zero or infinite resistance.

#### hanhan100

Joined Apr 8, 2022
6
I meant something like this :

View attachment 269780

If it's unreadable then I'll write it again.
It is not wrong. The Norton current In = E/R and Norton resistance is R.
If you let R approaches 0 you would get In apporaches infinity and R appoaches 0.
I don't see anything wrong with this. Why do you thing that it is impossible (in practice?)?

#### MrAl

Joined Jun 17, 2014
10,920
I meant something like this :

View attachment 269780

If it's unreadable then I'll write it again.
Hi again,

Take a look...

If you have 10 amps and 0 Ohms in parallel with 6 Ohms, the Thevenin voltage is 10*0=0 and the resistance is 0*6/(0+6)=0.
If you have 6 amps and 0 Ohms in parallel with 46 Ohms, the Thevenin voltage is 6*0=0 and the resistance is 0*46/(0+46)=0.
If you have 106 amps and 0 Ohms in parallel with 14 Ohms, the Thevenin voltage is 106*0=0 and the resistance is 0*14/(0+14)=0.
If you have Ix amps and 0 Ohms in parallel with R Ohms, the Thevenin voltage is Ix*0=0 volts and the resistance is 0*R/(0+R)=0 Ohms.

So in every case the Thevenin voltage is 0v and the resistance is 0 Ohm.
If that makes you happy then you are good to go There may be one exception depending on how you look at it and that is if the current goes toward infinite and the resistance goes toward zero. You may then make an argument that the voltage is exactly 1 volt. Since we cant really have infinite current though this exception really isnt that important.