1845 – Germany
‘First law (Junction law): At any junction point in an electrical circuit, the sum of all currents entering the junction must equal the sum of all currents leaving the junction’
‘Second law (Loop law): For any closed loop in an electrical circuit, the sum of the voltages must add up to zero’
In equation form the first law is I = I1 + I2 + I3 + I4 +… where I is the total current and I1, I2, I3 etc. are the separate currents.
Second law is V = V1 + V2 + V3 + … where V is the total voltage and V1, V2, V3 etc. are the separate voltages.
These laws are an extension of OHM‘s law and are used for calculating current and voltage in a network of circuits. Kirchhoff formulated these laws when he was a student at the University of Konisburg.
Kirchhoff also showed that objects that are good emitters of heat are also good absorbers. This is Kirchhoff’s law of radiation.