About Kirchhoff Current Law
Kirchhoff Current Law is a basic rule for any electrical node. It says current entering a junction must equal current leaving it. The idea follows charge conservation. Charge cannot disappear at a wire connection. It also cannot build forever in a steady circuit. Because of that, a balanced node has a net current of zero.
This calculator treats entering current as positive. It treats leaving current as negative. You can enter measured or planned branch currents. The tool then adds signed values. It shows total current entering the node. It also shows total current leaving the node. The difference is the KCL error. A small error may come from rounding, meter tolerance, or sensor drift.
Why Signed Current Matters
Signed current prevents confusion in busy circuits. A branch may act as a load in one condition. It may act as a source in another condition. Direction is therefore as important as magnitude. The calculator lets each branch be marked entering or leaving. If one current is unknown, leave its value blank. The tool solves the missing branch needed for balance.
You can use amperes, milliamperes, microamperes, or kiloamperes. Internally, all entries are converted to amperes. This keeps the algebra consistent. Results are then shown in your selected display unit.
Practical Electrical Uses
KCL checks are useful in circuit design, repairs, and lab work. They help verify junction equations before solving a larger network. They also help compare simulated currents with measured values. Power supply outputs, resistor networks, transistor bias nodes, and parallel loads can all be checked.
For field work, the percent imbalance is helpful. It compares the signed error with the larger total current. A high value may show a wrong direction, bad reading, missing branch, or wiring issue.
Accuracy Tips
Use the same reference node for every branch. Keep direction labels consistent. Enter RMS values when checking AC circuits by magnitude. Use phasor methods separately when phase angles matter. Do not mix peak and RMS readings. Add every branch connected to the node. For best results, use meter ranges that match the expected current. Record the tolerance used. Then export the table for your notes. Keep notes clear for future reviews and safer maintenance.