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Kirchoff's laws

Kirchoff's current law essentially states that there has to be a circuit, i.e., that there has to be a return conductor.

Kirchoff's voltage law can be considered the basis of electronics, where electronics means a circuit containing various elements.  Kirchoff's voltage law provides a means for unifying the behavior of different types of circuit elements by stating that the sum of the voltages contributed by each circuit element around any closed circuit is zero; see Fig.2.  For AC circuits Kirchoff's voltage law is superseded by Faraday's law and invoking Kirchoff's voltage law when Faraday's law should be used leads to incorrect conclusions regarding the cause of ground loops. 

Figure 2. Kirchoff's voltage law: sum of voltages around circuit (measured in same sense) is zero, i.e., V1+V2+V3+V4 =0.

Troubleshoot ground loops with ease
without disconnecting anything!
US Patent 7,791,353 B2