Circuit with only resistors and multiple batteries

[driedupfish]

in a simple circuit with only resistors and multiple batteries and multiple loops, which side is the positive and negative on the resistors? I am referring to the case of Kirchhoff rule in which I have to come up with equations to solve for current or voltage. But I got confused on voltage drop and gain thing.

 

[weichi]

Do you mean "what side is positive and negative" in the real circuit, or what side should you choose + and - when solving the circuit?

If the former - you can't tell until you solve the circuit!

If the later - I always choose a direction for the current in each branch, voltage drops in the direction of the current. I thought of the choice of direction as a guess; if a current turns up negative, it means I guessed wrong.

Does this help?

 

[driedupfish]

yes, thanks a lot.