| An Electrical Connector is an electromechanical device used to join electrical terminations and create an electrical circuit. Most electrical connectors have a gender – i.e. the male component, called a plug, connects to the female component, or socket. The connection may be removable (as for portable equipment), require a tool for assembly and removal, or serve as a permanent electrical joint between two points. An adapter can be used to join dissimilar connectors. |
| Thousands of configurations of connectors are manufactured for power, data, and audiovisual applications. Electrical connectors can be divided into four basic categories, differentiated by their function:- inline or cable connectors permanently attached to a cable, allowing it to be plugged into another terminal (either a stationary instrument or another cable)- chassis or panel connectors which are permanently attached to a piece of equipment, allowing users to connect a cable to a stationary device- PCB mount connectors soldered to a printed circuit board, providing a point for to a cable or wire to be attached: (e.g. pin headers, screw terminals, board-to-board connectors)- splice or butt connectors (primarily insulation displacement connectors) which permanently join two lengths of wire or cableIn computing, electrical connectors are considered a physical interface and constitute part of the physical layer in the OSI model of networking. |
| Physical Construction In addition to the classes mentioned above, connectors are characterised by their pinout, method of connection, materials, size, contact resistance, insulation, mechanical durability, ingress protection, lifetime (number of cycles), and ease of use. It is usually desirable for a connector to be easy to identify visually, rapid to assemble, inexpensive, and require only simple tooling. In some cases an equipment manufacturer might choose a connector specifically because it is not compatible with those from other sources, allowing control of what may be connected. No single connector has all the ideal properties for every application; the proliferation of types is a result of the diverse yet specific requirements of manufacturers. |
| Materials Electrical connectors essentially consist of two classes of materials: conductors and insulators. Properties important to conductor materials are conductivity, mechanical strength, formability, and resilience. Insulators must have a high electrical resistance, withstand high temperatures, and be easy to manufacture for a precise fit.
Electrodes in connectors are usually made of copper alloys, due to their good conductivity and malleability. Alternatives include brass, phosphor bronze, and beryllium copper. The base electrode metal is often coated with another inert metal such as gold, nickel, or tin. This increases the electrical conductivity and durability. For example, copper alloys have favorable mechanical properties for electrodes, but are hard to solder and prone to corrosion. Thus, copper pins are usually coated with gold to alleviate these pitfalls, especially for analog signals and high reliability applications. Contact carriers which hold the parts of a connector together are usually made of plastic due to its insulating properties, and housings or backshells can be made of molded plastic or metal. |
Failure Mode The majority of connector failures result in intermittent connections or open contacts:
High temperatures can also cause failure in connectors, resulting in an "avalanche" of failures – ambient temperature increases, leading to a decrease in insulation resistance and increase in conductor resistance; this increase generates more heat, and the cycle repeats. Fretting (so-called dynamic corrosion) is a common failure mode in electrical connectors that have not been specifically designed to prevent it, especially in those that are frequently mated and de-mated. Surface corrosion is a risk for many metal parts in connectors, and can cause contacts to form a thin surface layer which increases their resistance, thus contributing to heat buildup and intermittent connections. However, remating or reseating a connector can alleviate the issue of surface corrosion, since each cycle scrapes a microscopic layer off the surface of the contact(s), exposing a fresh, unoxidised surface. |
