Electrical connector

An electrical connector is a conductive device for joining electrical circuits together. The connection may be temporary, as for portable equipment, or may require a tool for assembly and removal, or may be a permanent electrical joint between two wires or devices. There are hundreds of types of electrical connectors. In computing, an electrical connector can also be known as a physical interface.



terminal is a simple type of electrical connector that connects two or more wires to a single connection point. Wire nuts are another type of single point connector.


Terminal blocks of various types.
Terminal blocks
Terminal blocks (also called terminal boards or strips) provide a convenient means of connecting individual electrical wires. They are usually used to connect wiring among various items of equipment within an enclosure or to make connections among individually enclosed items. Since terminal blocks are readily available for a wide range of wire sizes and terminal quantity, they are one of the most flexible types of electrical connector available. Some disadvantages are that connecting wires is more difficult than simply plugging in a cable and the terminals are generally not very well protected from contact with persons or foreign conducting materials.

One type of terminal block accepts wires that are prepared only by removing (stripping) a short length of insulation from the end. Another type accepts wires that have ring or spade terminal lugs crimped onto the wires. Printed circuit board (PCB) mounted terminal blocks allow individual wires to be connected to the circuit board. PCB mounted terminal blocks are soldered to the board, but they are available in a pull-apart version that allows the wire-connecting half of the block to be unplugged from the part that is soldered to the PCB.


Crimp-on terminals
Most types of crimp-on terminals (or lugs) are attached to wires to allow the wires to be easily connected to screw terminals and fast-on or quick-disconnect terminals. There are also crimp-on terminals for connecting two wires together either permanently or with disconnect capability. Crimp-on terminals are attached by inserting the stripped end of a stranded wire into the tubular portion of the terminal. The tubular portion of the terminal is then compressed tightly around the wire or crimped by squeezing it with a special crimping pliers.


Insulation displacement connectors
Since stripping the insulation from wires is time-consuming, many connectors intended for rapid assembly use insulation-displacement connectors so that insulation need not be removed from the wire. These generally take the form of a fork-shaped opening in the terminal, into which the insulated wire is pressed and which cut through the insulation to contact the conductor within. To make these connections reliably on a production line, special tools are used which accurately control the forces applied during assembly. If properly assembled, the resulting terminations are gas-tight and will last the life of the product. A common example is the multi-conductor flat ribbon cable used in computer disk drives; to terminate each of the many (approximately 40) wires individually would be slow and error-prone, but an insulation displacement connector can terminate all the wires in (literally) one stroke. Another very common use is so-called "punch down" blocks used for terminating telephone wiring.

Insulation displacement connectors are usually used with small conductors for signal purposes and at low voltage. Power conductors carrying more than a few amperes are more reliably terminated with other means, though "hot tap" press-on connectors find some use in automotive applications for additions to existing wiring.


Plug and socket connectors
Plug and socket connectors are usually made up of a male plug and a female socket, although hermaphroditic connectors exist, such as the original IBM token ring LAN connector. Plugs generally have one or more pins or prongs that are inserted into openings in the mating socket. The connection between the mating metal parts must be sufficiently tight to make a good electrical connection and complete the circuit. When working with multi-pin connectors, it is helpful to have a pinout diagram to identify the wire or circuit node connected to each pin.


4-conductor hermaphrodite connector for token-ring attachment.
Detail of mating surfaces of hermaphrodite connector.
Transistor switch module with large screw connectors and small fast-on connectors.



Component and device connectors
Electrical and electronic components and devices sometimes have plug and socket connectors or terminal blocks, but individual screw terminals and fast-on or quick-disconnect terminals are more common. Small components have bare lead wires for soldering. They are manufactured using casting

8P8C connector
Main article: 8P8C
8P8C is short for "eight positions, eight conductors", and so an 8P8C modular connector (plug or jack) is a modular connector with eight positions, all containing conductors. The 8P8C modular plugs and jacks look very similar to the plugs and jacks used for FCC's registered jack RJ45 variants, although the true and extremely uncommon RJ45 is not really compatible with 8P8C modular connectors. It neither uses all eight conductors (but only two of them for wires plus two for shorting a programming resistor) nor does it fit into 8P8C because the true RJ45 is "keyed". The connector is probably most famous for its use in Ethernet and widely used on CAT5 cables.


DE-9 connector

A male DE-9 plug.The DE-9 (9 pin D-shell connector) is a type of D-subminiature electrical connector most commonly used for the RS 232 serial port on the IBM AT and compatible computers. DB-9 is a common misnomer for the DE-9. (A true DB-9 connector would have 9 pins in a connector the shape and size of a DB-25, the other 16 pins would just be missing.) The DE-9 connector is used in many different applications, for computers, telecommunications, and test and measurement instruments. A few examples are older monitors (MGA, CGA, EGA), the Commodore 64, MSX, Apple II, Amiga and Atari joysticks and mouses, and game consoles such as Atari, Sega and Amiga.


USB connectors
Main article: USB

A male USB series A plugThe Universal Serial Bus is a serial bus standard to interface devices, founded in 1996. It is currently widely used among PCs, Apple Macintosh and many other devices. There are several types of USB connectors, and some have been added as the specification has progressed. The most commonly used is the (male) series "A" plug on peripherals, when the cable is fixed to the peripheral.If there is no cable fixed to the peripheral the peripheral always needs to have a USB "B" socket.In this case a USB "A" plug to a USB "B" plug cable would be needed. USB "A" sockets are always used on the host PC and the USB "B" sockets on the peripherals. It is a 4-pin connector, surrounded by a shield. There are several other connectors in use, the mini-A, mini- B and mini-AB plug and socket(Added in the On-The-Go Supplement to the USB 2.0 Specification).

An RF connector is an electrical connector designed to work at radio frequencies in the multi-megahertz range. RF connectors are typically used with coaxial cables and are designed to maintain the shielding that the coaxial design offers. Better models also minimize the change in transmission line impedance at the connection. Mechanically they provide a fastening mechanism (thread, bayonet, braces, push pull) and springs for a low ohmic electric contact while sparing the gold surface thus allowing above 1000 reconnects and reducing the insertion force.




Others
For Wi-Fi antenna are used the R-TNC connectors.

This article is from http://en.wikipedia.org/wiki/Electrical_connectors All text is available under the terms of the GNU Free Documentation License(http://en.wikipedia.org/wiki/Wikipedia:Text_of_the_GNU_Free_Documentation_License).