

Kirchoff's Rules
state what we've seen already

The sum of the changes in potential encountered in a
complete traversal of any circuit must be zero. (Each point has a
unique potential value.)

The sum of the currents entering any junction must be
equal to the sum of the currents leaving that junction. (Charge is conserved.)
To apply these rules, there are some guidelines
that are worth following:

Draw & label the current through each component.

Pick directions to "travel" though a loop.

If you go across the battery from  to + then the potential
difference is positive.

If you go from + to  (opposite the way the current
would flow if this were the only battery), then the difference is negative.

If you go across a resistor with the current, then the
voltage difference is negative.

If you go across the resistor opposite the direction
you've drawn the current, the voltage is positive.

Donít worry if you've drawn the current in the right
direction, as long as youíre consistent it will work out. If the
current is negative, then it travels opposite to the way you've drawn it.

Start writing down the various loop equations.
There may be more equations than you need.

Do lots of algebra.

