Kirchhoff’s laws
Kirchhoff’s laws is an interactive experiment in Circuit Builder, a free simulation from StudyFi Lab that runs right in your browser.
First law: the current flowing into a junction equals the current flowing out, ΣI = 0 — ammeters A1, A2 and A3 meet at one node. Second law: around a closed loop the voltages add up to zero, ΣU = 0 — the battery voltage V1 equals the drops across R1 and R3 (V2 + V3). A negative reading means the current flows against the meter’s arrow.
Try this: Change the voltage of battery B2 until ammeter A2 reads zero. Then keep going and watch its sign flip.
Frequently asked questions
What does the “Kirchhoff’s laws” experiment show?
First law: the current flowing into a junction equals the current flowing out, ΣI = 0 — ammeters A1, A2 and A3 meet at one node. Second law: around a closed loop the voltages add up to zero, ΣU = 0 — the battery voltage V1 equals the drops across R1 and R3 (V2 + V3). A negative reading means the current flows against the meter’s arrow.
How do I try “Kirchhoff’s laws”?
Change the voltage of battery B2 until ammeter A2 reads zero. Then keep going and watch its sign flip.
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