Read Nodal Analysis: Let Current Balance Find the Potential
At a junction, do not try to simplify the whole network first. Give the unknown node a potential V and write the current through every branch using its voltage difference.
Electricity questions depend on identifying charge, a conducting path and the condition that controls current or magnetic effect.
Separate charge, current and the path between them
Charge is a property · current needs a conducting path
Charge is a property; current needs a conducting path. Decide first whether the question concerns charging, resistance, current or earthing.
One equation at the node
Kirchhoff's current law says the sum is zero.
Equal resistances shortcut
When every branch resistance is the same, the node potential is the arithmetic mean of the connected known potentials. Derive it once from KCL so you know when it applies.
Read the sign
A negative branch current only means actual current is entering the node; it is not an error.
OlympIQ exam lens
- ✓Assign one unknown node potential.
- ✓Write each branch as a voltage difference over resistance.
- ✓Use a single current-direction convention.
Do not average voltages if the branch resistances are unequal; use conductance-weighted averaging through KCL.
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