DEMO 1 - Slide the mouse over the
gray rectangle to obtain Kirchhoff's Current Law Equation as the sum of the
currents when all the reference arrows are pointing away from the node.
DEMO 2 - Slide the mouse over the gray rectangle to see how the choice
of reference direction for I3 affects Kirchhoff's Current Law Equation. Note
that each plus represents one coulomb/sec of equivalent positive charge.