- #1

- 30

- 6

Derived from this circuits 3 nodes are 3 equations using the NodeVoltageMethod

1. (V1--40)/12 + 5 + (V1-V2)/20 + V1/25 = 0

2. (V2-V1)/20 + (V2-V3)/40 - 7.5 - 5 = 0

3. V3/40 + (V3-V2)/40 + 7.5 = 0

The only pattern I can see here is that if it is at node 1 then it is always the node voltage belonging to node 1 (which is V1) minus something else. I know that "this" minus "this" gives you the voltage across the horizontal or sometimes vertical resistor but I don't know WHY. Why do you minus voltages from each other.

1. (V1--40)/12 + 5 + (V1-V2)/20 + V1/25 = 0

2. (V2-V1)/20 + (V2-V3)/40 - 7.5 - 5 = 0

3. V3/40 + (V3-V2)/40 + 7.5 = 0

The only pattern I can see here is that if it is at node 1 then it is always the node voltage belonging to node 1 (which is V1) minus something else. I know that "this" minus "this" gives you the voltage across the horizontal or sometimes vertical resistor but I don't know WHY. Why do you minus voltages from each other.