influx
- 162
- 1
How can one spot a node?
I know that the blue dots are nodes but why isn't the red dot a node?
Thanks
Understanding Nodes: Identifying and Differentiating Them
- Thread starter influx
- Start date
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
5 replies · 2K views
How can one spot a node?
I know that the blue dots are nodes but why isn't the red dot a node?
Thanks
- 4,041
- 2,084
All three dots are nodes.
- 19,385
- 15,622
Cool it with the massive fonts. It's SCREAMING and is not necessary.
A node is just any place where two or more elements come together. As scott said, all three colored dots are nodes, and I would add that the ground is a node as well.
A node is just any place where two or more elements come together. As scott said, all three colored dots are nodes, and I would add that the ground is a node as well.
influx
- 162
- 1
phinds said:
.Scott said:
I didn't create the image, its just a screen shot from my university lectures. I apologise.
When you say ''element'' do you just mean three ''branches'' of the circuit?
If so, why is there a node at the place of the red dot in the image below?
Thanks!
- 12,828
- 1,673
A node, in this context, is any point in the circuit at which you want to find the current, voltage, or some other property.
Topologically, in the second circuit, the red node with the (-) attached is equivalent to the ground.
Topologically, in the second circuit, the red node with the (-) attached is equivalent to the ground.
Circuit elements (or components) are joined together by wires. Where wires from components connect there is a node. Every wire in the circuit is part of some node.
An "element" just means a circuit component, such as a voltage source, current source, resistor, capacitor, or inductor. You can define a node any place two or more such elements join. Sometimes it is convenient to define nodes in the middle of branches because you happen to be interested in finding the potential there. Otherwise such nodes are considered to be "non-essential" nodes, and aren't required for finding the potentials at other "essential" nodes.
The "V" node in the second circuit is an example of a non-essential node. The two resistors (2 and 6 Ohms) comprise a single series branch between nodes V1 and V2. Those resistors could easily be combined into a single 8 Ohm resistor and one could proceed to find the potentials of node V1 and V2 without difficulty (and with one less node equation). The node V was introduced, apparently, because it was desired to find the potential there.
An "element" just means a circuit component, such as a voltage source, current source, resistor, capacitor, or inductor. You can define a node any place two or more such elements join. Sometimes it is convenient to define nodes in the middle of branches because you happen to be interested in finding the potential there. Otherwise such nodes are considered to be "non-essential" nodes, and aren't required for finding the potentials at other "essential" nodes.
The "V" node in the second circuit is an example of a non-essential node. The two resistors (2 and 6 Ohms) comprise a single series branch between nodes V1 and V2. Those resistors could easily be combined into a single 8 Ohm resistor and one could proceed to find the potentials of node V1 and V2 without difficulty (and with one less node equation). The node V was introduced, apparently, because it was desired to find the potential there.