Comparison between Field Theory and Circuit Theory

Comparison between Field Theory and Circuit Theory

AU : May-10,11,12,14,16,17,18, Dec.-12,14,18

• In general, we can express total electric field as sum of the electric field related to e.m.f.s  and the electric field due to charges and currents 

• Now the total electric field is the ratio of current density to the conductivity i.e.,

Also we can write, using general field relations for time varying fields (refer section 9.4.1),

• Substituting equations (9.9.2) and (9.9.3) in equation (9.9.1), we get,

• Let us consider series circuit consisting resistor, inductor and capacitor driven by a generator V_g as shown in the Fig. 9.9.1  (a). Its equivalent representation is as shown in the Fig. 9.9.1 (b).

• Integrating all the terms in equation (9.9.4) around circuit in clockwise direction we get,

• Now the integration of LHS term is generator voltage Vg, so we can write,

Review Questions

1. Explain the relationship between the field theory and circuit theory using a simple RLC series circuit.

2. Compare the field theory and circuit theory.

AU : May-11,12,14, Marks 8

3. Discuss the relation between field theory and circuit theory.

AU : Dec.-12, Marks 8