Kirchhoff's Laws

Kirchhoff's Current Law

Kirchhoff's first law, abbreviated as KCL, says the sum of all currents that enter or leave a junction or node equals 0.   Or you could say the current going into is equal to the current going out of a junction or node.

• \( I_a - I_b =0 \)
• \( I_a + I_b + I_c - I_d - I_e = 0 \)

Kirchhoff's Voltage Law

Kirchhoff's second law, abbreviated as KVL, says the sum of all voltages in an circuit loop is 0.

• \( V_a - V_b = 0 \)
• \( V_a + V_b + V_c - V_d - V_e = 0 \)