Chapter 5
First-order（一阶） circuits
In the chapter we shall introduce the study of
circuits characterized by a single energy-storage
element— a capacitor or a inductor,It will be shown
that the equations describing such a circuit may be
put in a form involving an unknown variable and its
first derivative,Such an equation is referred to as a
first-order differential equation,thus we shall refer to
circuits which contain only a single energy-storage
element as first-order circuits.