[sdiy] Calculating current out of a two resistor voltage divider?

[David G Dixon]

Each node (where three wires branch off) is at a specific voltage, V.

Each wire carries a specific current, I, equal to [V(1) - V(2)]/R (where
current flow is taken to be from node 1 to node 2).

All currents into each node add up to zero (since charge cannot accumulate
at the node).  Put another way, the currents into each node equal the
currents out.

With these simple rules, the various models for impedance, and a bit of
algebra, you can analyze just about any circuit.