Mechanical characteristics
Leg sequence
Some connectors are designed so that certain pins make contact before others when inserted, and break first when disconnected. This is often used in power connectors to protect equipment, for example by connecting safety ground first. It is also used for digital signals, as a method to correctly sequence connections in hot exchange.
Notches or orientation pin
Many connectors are keyed with some mechanical component (sometimes called a keyway), which prevents mating in the wrong orientation.[15] This can be used to prevent mechanical damage to the connectors, from being stuck at the wrong angle or in the wrong connector, or to avoid incompatible or dangerous electrical connections, such as plugging an audio cable into a power outlet. Orientation control also prevents symmetrical connectors from being connected in the wrong orientation or polarity. Coding is especially important in situations where there are many similar connectors, such as in signal electronics. For example,
Locking mechanisms
Some connector housings are designed with locking mechanisms to prevent inadvertent disconnections or poor environmental sealing. Locking mechanism designs include locking levers of various types, screws, screw housings, push-pull connectors, and lever or bayonet systems. Some connectors, especially those with a large number of contacts, require large forces to connect and disconnect. Application, enclosures with locking mechanisms can be tested under various environmental simulations including physical shock and vibration, water splash, dust, etc. to ensure the integrity of the electrical connection and enclosure joints.
Back covers
Backshells are a common accessory for industrial and high-reliability connectors, especially circular connectors.[13] Backshells typically protect the connector and/or cable from environmental or mechanical stresses, or shield it from electromagnetic interference.[17] There are many types of backshells for different purposes, including various sizes, shapes, materials, and protection levels. Backshells typically lock onto the cable with a clamp or molded boot, and may be threaded for attachment to a mating receptacle.[18] Backshells for military and aerospace use are regulated by SAE AS85049 within the United States.[19].
Hyperboloid contacts
To ensure signal stability in extreme environments, the traditional pin and socket design may be inadequate. Hyperboloid contacts are designed to withstand more extreme physical demands, such as vibration and shock.[15] They also require around 40% less insertion force[20] – as low as 0.3 Newton per contact,[21]{snd}}prolonging life and, in some cases, offering an alternative to zero insertion force connectors.[22][20].
In a connector with hyperboloid contacts, each female contact has several equidistant longitudinal wires twisted into a hyperbolic shape. These threads are very resistant to tension, but remain somewhat elastic, so they essentially function as linear springs.[23][24] When inserting the male pin, the axial wires in the middle of the socket deflect, wrapping around the pin to provide a series of contact points. The internal threads that form the hyperboloid structure are usually anchored at each end by bending the tip into a groove or notch in the casing.[25].
Although hyperboloid contacts may be the only option for making a reliable connection in some circumstances, they have the disadvantage of taking up a larger volume in a connector, which can cause problems for high-density connectors.[20] They are also significantly more expensive than traditional pin-and-socket contacts, which has limited their acceptance since their invention in the 1920s by Wilhelm Harold Frederick.[26] In the 1950s, Francois Bonhomme popularized the contacts. hyperboloids with their "Hypertac" connector, which was later acquired by Smiths Group. Over the following decades, the connectors steadily gained popularity, and are still used for medical, industrial, military, aerospace, and railway applications (especially trains in Europe).[23].
pogo pins
Pogo pin or spring-loaded connectors are commonly used in consumer and industrial products, where mechanical strength and ease of use are a priority.[27] The connector consists of a barrel, a spring, and a plunger. They are found in applications such as the MagSafe connector&action=edit&redlink=1 "MagSafe (power connector for laptops) (not yet drafted)") where a quick disconnect is desired for safety. Because they rely on spring pressure, not friction, they can be more durable and less damaging than the traditional pin and socket design, leading to their use in circuit testing.[28].
Crown spring connectors
Crown spring connectors are commonly used for higher current flows and industrial applications. They have a high number of contact points, providing a more electrically reliable connection than traditional male and female connectors.[29].