What is a circuit in general?

electric circuit, unbroken path along which an electric current exists or is intended or able to flow. ... Two general circuit classifications are series and parallel. The elements of a series circuit are connected end to end; the same current flows through its parts one after another.

answer; economic order quantity;

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.