Consider now a structural definition of a connector. There are four basic components in a connector. They are:
A. the connector housing
B. the contact springs
C. the contact finish
D. the contact interface
This chapter will provide a basic introduction to connector housings, contact springs and contact finishes with details to be provided in following chapters. The contact interface will be discussed in detail in this chapter.
A few general comments are appropriate at this point. All connectors consist of two mating halves, a plug half which is inserted into the receptacle half. This plug/receptacle structure exists in both the housings and the contact springs. With respect to the contact springs, as mentioned earlier, in most connectors the plug contact deflects a spring system in the receptacle contact. This spring deflection produces the contact force which creates and maintains the desired metal-to-metal contact interface.
Consider these components as realized in a wall plug/receptacle connector as shown in Figure 1.2. The housing of the plug connector is overmolded onto the straight copper alloy plug contacts which are crimped onto the lamp cord wire. The housing of the receptacle connector is assembled around the copper alloy receptacle contacts which are pressure connected to the house wiring. When the connector halves are mated, the receptacle contact spring is deflected by the plug contact creating the contact interface. In this example, there is no contact finish, no plating or coating, on the contacts. The functions of a contact finish will be discussed in a following section.
A cross section of a more typical connector is shown in Figure 1.2 with all components illustrated. Each of the connector components will be discussed briefly in this chapter and in detail in the following chapters.