KIRCHHOFF'S LAWS
Kirchhoff's laws are very useful in solving circuits which cannot be easily solved by Ohm's law. First Law: "The algebraic sum of all the currents meeting at any junction point in an electric circuit is zero". This law relates to the currents at the junction points of a circuit. Consider four wires meeting at a point O and carrying currents I1, I2, I3 and I4 as shown in fig. Sign conventions of currents: ●Currents flowing towar ds junction point O taken as positive(+ve) sign, and ●Currents flowing away from junction point O taken as negative(-ve) sign. According to Kirchhoff's first law, Algebraic sum of currents meet at a junction point '0' = 0 i.e. ∑ I = 0 And according to sign conventions of currents I1 and I2 = +ve, I3 and I4 = -ve Therefore Kirchhoff's first law is (I1) + (I2) + (- I3) + (- I4) = 0 or (I1) + (I2) - (I3) - (I4) = 0 or (I1) + (I2) = (I3) + (I4) i.e Sum of incoming currents = Sum of outgoing currents. Therfore Kirch...