Abstract: This paper firstly reviews the basic content of“field”and“circuit”，compares them from the primary structure and lists the relationship between the two physical quantities. Then，from the perspective of circuit abstraction in electromagnetics，it clarifies the modeling method of“field”derivative“circuit”and“Fourth class” basic passive components deductive. Finally，the application example is given: the resonance photoacoustic spectroscopy of biological tissue detection.

Key words: circuit abstraction, “field”and“circuit”, basic passive component deduction, electromagnetics