# Can someone explain this to me, by using super nodal analysis: vo = 5.6V

#### arthur442

Joined Jul 10, 2021
18

#### ericgibbs

Joined Jan 29, 2010
14,702
hi 442,
E

#### arthur442

Joined Jul 10, 2021
18
hi 442,
E

i think my mistake is with the super node, but i don't know what is wrong.

#### Jony130

Joined Feb 17, 2009
5,289
I do not see 2mA current source to be included in your nodal analysis?

#### arthur442

Joined Jul 10, 2021
18
I do not see 2mA current source to be included in your nodal analysis?
Stupid of me, that's indeed my fault, thank you for helping

#### MrAl

Joined Jun 17, 2014
8,616
Stupid of me, that's indeed my fault, thank you for helping
It also helps to post your results so members here can check it over for you.

In the mean time here are the two graphics cleaned up just a little bit to make them more readable

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#### RBR1317

Joined Nov 13, 2010
677
Stupid of me,
Call it what you will, but it can be difficult to focus on too many details at the same time (such as writing a node equation for a complex circuit while trying to keep track of all that is in the node.) That is why my first step in nodal analysis is to color-code & label the nodes (and designate a ground node). But if a node already has a name (Vo) don't give it a new name (Vc). Also, I see that you are already structuring the node equations such that every voltage term in the node equation begins with the voltage of that node. Advance preparation eliminates the distractions that cause stupid errors.

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#### arthur442

Joined Jul 10, 2021
18
Call it what you will, but it can be difficult to focus on too many details at the same time (such as writing a node equation for a complex circuit while trying to keep track of all that is in the node.) That is why my first step in nodal analysis is to color-code & label the nodes (and designate a ground node). But if a node already has a name (Vo) don't give it a new name (Vc). Also, I see that you are already structuring the node equations such that every voltage term in the node equation begins with the voltage of that node. Advance preparation eliminates the distractions that cause stupid errors.
Thank you, I will try to apply the next time

#### neonstrobe

Joined May 15, 2009
180
Not sure if RBR's comment was to agree or disagree or just observe, but when I write nodal equations I generally make the equations follow clockwise round the circuit and start with whatever node voltage is on the left, say, of the node being evaluated and work around before grouping all the voltage terms together. That gives you a term for the current into that node, in turn.
I find that it reduces the chances of missing an input that way, like your 2mA.
You don't have to do it that way of course, but if you start with the node voltage you still have to make sure all its neighbours are accounted for.

#### MrAl

Joined Jun 17, 2014
8,616
Hello there,

A simple way to think of a super node in circuit analysis is to recognize that the source is a short circuit when writing one equation while it is an actual source with the actual stated source value when writing another equation. One equation is an equation for current, the other is for voltage. Because of this dual nature i like to call this kind of theoretical operation an "aniselectric short" or "anisoelectric short". You can also call it an "aniselectronic short" but the word aniselectric sounds more general. We could also call it an "aniselectric source" in theory but that is not as general so i stick mostly to "aniselectric short" which simply indicates that the function of the source (or more generally the short itself) is taken to function one way for one equation and another way for another equation. This of course implies that if we were to measure these quantities we would of course measure two different values depending on how we make the measurement and hence the prefix "anis" or "aniso".
Because this is so general there are other uses for this concept also.

For the sake of etymology the word "aniselectric" is more proper than "anisoelectric" because "electric" starts with a vowel so we drop the 'o'.

It is also interesting that there are other "aniselectric" components that we usually dont realize have that property.

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