# How do you find the magnitude of current?

So we are working on Kirchhoffs law.

So I can basically navigate through junction rule and loop rule, but I want to know if there is any other way to find the magnitude of current.

I have no idea how to go about doing physics problems, you guys are always great at explaining. Thanks

• Anonymous
3 days ago

You will probably be given a circuit that is not real, usually with 2 batteries, etc. You will have to use Kirchhoff’s laws to solve it, but the actual circuit would not exist in the real world.

• ?
3 days ago

They tend to be a bit smaller than sultanas, about half the size of jumbo raisins. Unless you soak them in brandy.

In most fruit cake recipes it really doesn’t matter how big they are, and there’s a bit of room for error on the quantity. If I don’t have scales handy I tend to guesstimate, and it usually works out fine. If you dust them with flour beforehand they won’t sink to the bottom of the cake.

• ?
3 days ago

What ever you measure in electrical circuits and electronic circuits are the magnitudes of currents. So you do not worry about.

• Dixon
3 days ago

As an actual electronic engineer for 20 years I have never seen anyone use Kirchhoff’s laws other than simply summing the current into one node (which we think of as |in| = |out|) or, summing the voltage round a loop (which we think of as “the voltage between two nodes is the same by any path”). That is to say, we never set up various loops of unknown voltages and currents and solve simultaneous equations.

We use Star-Delta transformations and swapping between Norton and Thevenin equivalent models. You probably haven’t met these yet but they are much easier (IMHO) than setting up the sort of equations you get with Kirchhoff. They basically allow an iterative step by step simplification and you can intuitively see if you have made a gross error.

• ?
3 days ago

As others have said, an example would let us give a better answer.

But I comment that Thevenin’s theorem, and use of star-delta and delta-star transformations, can simplify many problems.

• billrussell42
3 days ago

I find loop equations long and tedious, and prone to mistakes.

Where you can use other methods. One is superposition.

Yes, show an example.

edit, I agree that in real life you never use loop equations.

• ?
3 days ago

My favourite method is using linear algebra, if you post an example question I can work through it to show you how.