电子技术手册（英文版）

A passive electronic component is a circuit part that functions without an external power 

requirement. The most common passive components are resistors, capacitors, and inductors. 

Most of them have two leads. An axial-leaded component, as shown in Fig. 1-1, has leads 

projecting from each end of the component body aligned with the long axis of the part, while 

a radial-leaded component, as shown in Fig. 1-2, has parallel leads projecting at right angles 

from its body. Axial leads must first be bent 90° to insert them into the holes of circuit 

boards, while radial leads can typically be inserted directly into those holes without bending. 

However, both axial- and radial-leaded parts can be inserted by automatic machines.