Kirchhoff's Laws hold for any of the circuits because at a given junction the electric current distribute. The law states that the algebraic sum of the current at any junction is zero.

Nodal Analysis is primarily based on the application of Kirchhoff's Laws. Nodal Analysis uses Kirchhoff's Voltage Law (KVL) and Kirchhoff's Current Law (KCL) (and even Ohm's Law) to determine the voltage and current between each node of an electric circuit.

Kirchhoff (not 'Kirchoff') doesn't suggest any way of measuring current or voltage in a circuit. Kirchhoff's Voltage Law defines the relationships between potential differences around any closed loop within a circuit. Kirchhoff's Current Law defines the relationships between currents at any junction within a circuit. Kirchhoff's Laws may also be used to solve complex circuits ('complex' circuits are those circuits which are not series, parallel, or series-parallel).

Current and voltage may be measured with an ammeter and a voltmeter, respectively.

a closed path in a circuit in which no circuit element or node is encountered more than once.