Current Electricity
Class 12 · Current Electricity

Kirchhoff's Laws

2-loop circuit solved live. Currents update with KCL+KVL system.

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Key Notes

01

KCL: Σ_in I = Σ_out I at any junction (charge conservation).

02

KVL: Σ V = 0 around any closed loop (energy conservation).

03

Together: solve any DC circuit by writing one equation per loop.

Formulas

KCL

Junction rule.

KVL

Loop rule.

Important Points

Sign conventions: rising EMF (− to +) is +, drop across R in direction of I is +.

Number of independent KCL equations = junctions − 1; KVL = mesh count.

Kirchhoff's Laws notes from sciphylab (also known as SciPhy, SciPhy Lab, SciPhy Labs, Physics Lab). Class 12 physics revision for JEE Mains, JEE Advanced, NEET UG, AP Physics 1/2/C, SAT, and CUET-UG.