Connectors Tutorial

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The purpose of a connector is easy to describe: connectors bridge gaps between individual pieces of electronic equipment to make assembly, repair and upgrades easier to accomplish. By bridging the gap between individual wires, connectors provide contact between two conductive elements of an electronic system. The connection created enables electrical current (or light waves in the case of fiber optics) to flow from one conductor to the next.

Edward’s Publishing’s Encyclopedia of Connectors defines the connector thus: “An electromechanical device which permits two or more circuit elements to be electrically and mechanically separated and reconnected at will without disturbing any other elements of the circuit. A connector performs no circuit function and should have no effect on the electrical performance of the device to which it is attached. If the connectors of a device were eliminated and the corresponding wires joined together, the circuit would not be affected.”

When connectors are used to connect one set of wires to another, they are called wire-to-wire connectors. Wire-to-board connectors connect a wire to a Printed Circuit Board (PCB). Board-to-board connectors directly interconnect PCB’s.


Connectors facilitate the manufacture and assembly of electronic products by enabling designers to treat each subassembly as a unique, modular unit. Interconnection can then be accomplished at the most convenient time and place in the production process.

Connectors also facilitate the equipment repair process by allowing technicians to quickly and easily replace suspect components. Without opening black box cabinets and without introducing contaminants like solder and flux into the system, technicians can swap out suspect equipment and have a system back on line in a matter of minutes.

They also permit upgrades to electronic equipment without major disruptions to the overall system.  Connectors give engineers the flexibility to integrate new products and components into existing systems simply by maintaining a consistent connector specification.


While there is great variety in the makeup and design of each type of connector, as a family they generally share a common set of design elements and component parts. In order to function as a separable interconnected device, a connector must house the following elements:

  • Contact Interface: a mechanical means of joining the conductive contacts together under normal force
  • Contact Spring Members: a means of generating the normal force required to maintain the electrical path between conductive contact elements
  • Contact Finish: a means of protecting the contacts from corrosion, and for optimizing the lubricity and durability of the contact interface
  • Contact Housing: a means of holding the contacts and spring members in place and maintaining their exact position and alignment


Connectors are selected with consideration to electrical, mechanical and environmental requirements.

  • Electrical requirements include wire type and size, contact resistance, transfer impedance and current rating.
  • Mechanical specifications, such as thermal shock, vibration and durability indicate how well a connector will perform under critical stress factors.
  • Environmental requirements include moisture absorption, temperature resistance, corrosion and resistance to electromagnetic interference. Environmentally resistant connectors are required for interconnect systems which are subjected to fluids in combination with vibration, shock, thermal extremes and corrosion.
  • While the same basic connector design may be used for both signal and/or power distribution, power connectors use contacts designed specifically for the unique requirements of power distribution. This is due to the relatively higher current/voltage requirements of power applications and the temperature rise experienced by power connectors.

Quality Design Features

Design features of quality connectors include:

  • Programmed Coupling Sequence
  • Arc Quenching
  • Waterproof
  • Ruggedized