Nodal and Mesh Analysis vs Simple Ohms law?

[influx]

At high school we were taught basic circuit formulas such as V=IR, P=IV etc but now I am studying circuits in Engineering (at university)
we have been introduced to the techniques of nodal and mesh analysis.
My question is, when and why do we use these techniques rather than the aforementioned basic ones?

Also, when using V = IR, you just have positive values for voltage and current but with nodal and mesh analysis you can have negative?

I am a newbie to this so if someone could explain in simple terms how the 2 are related that would be great.

 

[SteamKing]

You can use the basic Ohm's Law formulas to analyze very simple circuits without too much trouble. In slightly more complex networks, if you can figure out the equivalent resistance of several discrete components, you're still good to go. However, if you have a very large or very complex network which has a lot of current loops, mesh analysis is the only tool which can be used to analyze such circuits.

Most of the circuits you encounter in your textbook examples are very simple, having only one or two current loops. For analyzing more complex circuits, having many different current sources and/or current loops, the mesh analysis technique will keep your head from exploding.

 

[influx]

You can use the basic Ohm's Law formulas to analyze very simple circuits without too much trouble. In slightly more complex networks, if you can figure out the equivalent resistance of several discrete components, you're still good to go. However, if you have a very large or very complex network which has a lot of current loops, mesh analysis is the only tool which can be used to analyze such circuits.

Most of the circuits you encounter in your textbook examples are very simple, having only one or two current loops. For analyzing more complex circuits, having many different current sources and/or current loops, the mesh analysis technique will keep your head from exploding.

Can you use Mesh analysis for simple circuits? E.g. the ones you would usually use V=IR for..

Thanks

 

[SteamKing]

Sure. Mesh analysis employs the same Ohm's law for simple circuits.

 

[rezeew]

I can understand your confusion about the different techniques used in circuit analysis. Nodal and mesh analysis are advanced techniques used to analyze more complex circuits, while Ohm's law is a basic formula used for simpler circuits.

The main reason we use nodal and mesh analysis is because they allow us to analyze circuits with multiple voltage sources and resistors connected in more complex configurations. These techniques provide a systematic approach to solving circuit problems and can handle circuits with a large number of components. On the other hand, Ohm's law is limited to simple circuits with only one voltage source and one resistor.

Regarding your question about negative values in nodal and mesh analysis, it is important to understand that voltage and current are relative quantities. This means that their values can be positive or negative depending on the reference point chosen. In nodal and mesh analysis, we choose a reference point or a reference direction, and any voltage or current value measured in the opposite direction will be negative. This is different from Ohm's law, where we usually assume a positive voltage and current direction.

To put it simply, nodal and mesh analysis are just more advanced versions of Ohm's law. They are based on the same principles, but they allow us to solve more complex circuits. I hope this explanation helps you understand the relationship between these techniques. Keep exploring and learning, and you will soon become more comfortable with these concepts.