# How to solve this problem?

#### moskan48

Joined Jan 25, 2013
12
Hello Friends!!!!!
how i solve this circuit by node voltage method?
i don't understand the point 1 and 2 ??

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#### WBahn

Joined Mar 31, 2012
25,090
Point 1 and 2 are simply two of the nodes. Since you already have a V1 in the diagram, let's call these Va and Vb, respectively.

If the bottom node is your 0V reference node, then what is Va (the voltage on Node A)? Taking into account that Node 2 is connected to Node 1 by a voltage source, what is Vb (the voltage on Node B)? Give Va and Vb, what is the node equation for V1?

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#### moskan48

Joined Jan 25, 2013
12
We take the sum of voltage 60 + I(pi) at point 1.
then why we not taking the sum of voltage 60 + I(pi) at point 2 because the the two source also connected to this point.

#### WBahn

Joined Mar 31, 2012
25,090
We take the sum of voltage 60 + I(pi) at point 1.
then why we not taking the sum of voltage 60 + I(pi) at point 2 because the the two source also connected to this point.
I have no idea what you mean by, "We take the sum of voltage 60 + I(pi) at point 1." Is that supposed to be an answer to one of the three questions I asked? If so, which one?

What is I(pi)?

Remember that voltages are always the difference in potential between two points. Whenever we talk about the voltage at a particular point, we are always implicitly stating it's voltage relative to a specific and agreed upon reference point. You still haven't indicated what your reference point is.