Kirchhoff and his bloody laws.

I am trying to teach myself Kirchhoff's laws for interviews this December since we weren't taught it at school. I am ok on circuits with one cell but I made this example up myself and I do not know where to go with it. I have attached a picture of said circuit with the current arrows in the direction I believe they go.

My main problem at the moment is on the connection B-E. I have two directions for current and I don't know in which way they go. Also, coming 'out of' B towards A, I don't know if the current from the cell on the far right combines with the current from the top left cell.

Please help if you can.

Original post by tazzik

I am trying to teach myself Kirchhoff's laws for interviews this December since we weren't taught it at school. I am ok on circuits with one cell but I made this example up myself and I do not know where to go with it. I have attached a picture of said circuit with the current arrows in the direction I believe they go.

My main problem at the moment is on the connection B-E. I have two directions for current and I don't know in which way they go. Also, coming 'out of' B towards A, I don't know if the current from the cell on the far right combines with the current from the top left cell.

Please help if you can.

Here's the circuit you posted.
I've marked in the currents and written a note on the current in EB.

It doesn't matter if you choose the wrong direction for a current.
Just be consistent with the addition and subtraction at the nodes.
When you do the calculation, if a current turns out to be negative, it just means it was going the other way to the one you initially decided.
The maths takes care of it.

(edited 13 years ago)

Reply 2

py0alb

3

Kirchhoffs laws are amazing. They're so damn obvious when you think about them, yet they are an incredibly useful tool in decyphering circuits.