R2 = 2 ohm
R3 = 3 ohm
R4 = 4 ohm
R5 = 5 ohm
R6 = 6 ohm

I2 = ?
I3 = ?
I4 = ?
I5 = ?
I6 = ?

Could you please help me solve this Kirchhoff exercise?

Thank all

 

Hi abc.
Welcome to AAC.
Check out this AAC Article, ask if you need assistance.
E
https://www.allaboutcircuits.com/textbook/direct-current/chpt-6/kirchhoffs-current-law-kcl/

also
https://www.allaboutcircuits.com/worksheets/kirchhoffs-laws/

 

I'm already familiar with Kirchhoff's laws—thanks anyway—but I don't know how to solve this particular problem.ericgibbs

 

One method would be to convert R2/R3/R4 from delta to a star network. After that it's much easier to calculate voltage/current across/through R5 and R6. If you have those you can get immediately the voltage/current across/through R2, R3 and finally R4 from the original network.

 

He likely hasn't been exposed to Y-Δ conversions yet.

You have two unknown voltages at the T intersections. Call them Va and Vb.

Then define your currents. I2 is not a current definition as it does not specify direction. Annotate your diagram with the quantities you will be using. The directions you assign to the currents are arbitrary -- flip a coin, if you must. But once you assign a direction, use it consistently throughout the problem.

For instance:



Now you can write each of the currents in terms of the four node voltages and apply KVL and KCL to solve for everything.

Beyond this, you need to show your best attempt to get further assistance.