Edge connector

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Two 44-pin edge connector sockets (blue objects) and matching circuit board. The Edge connector is 3.5 in (89 mm) long, with 22 contacts on each side 44EdgeConnector.jpg
Two 44-pin edge connector sockets (blue objects) and matching circuit board. The Edge connector is 3.5 in (89 mm) long, with 22 contacts on each side

An edge connector is the portion of a printed circuit board (PCB) consisting of traces leading to the edge of the board that are intended to plug into a matching socket. The edge connector is a money-saving device because it only requires a single discrete female connector (the male connector is formed out of the edge of the PCB), and they also tend to be fairly robust and durable. They are commonly used in computers for expansion slots for peripheral cards, such as PCI, PCI Express, and AGP cards.

Printed circuit board Board to support and connect electronic components

A printed circuit board (PCB) mechanically supports and electrically connects electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Components are generally soldered onto the PCB to both electrically connect and mechanically fasten them to it.

In electronics, a signal trace on a printed circuit board (PCB) is the equivalent of a wire for conducting signals. Each trace consists of a flat, narrow part of the copper foil that remains after etching. Signal traces are usually narrower than power or ground traces because the current carrying requirements are usually much less.

PCI Express computer expansion bus standard

PCI Express, officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common motherboard interface for personal computers' graphics cards, hard drives, SSDs, Wi-Fi and Ethernet hardware connections. PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism, and native hot-swap functionality. More recent revisions of the PCIe standard provide hardware support for I/O virtualization.


Socket design

Edge connector sockets consist of a plastic "box" open on one side, with pins on one or both side(s) of the longer edges, sprung to push into the middle of the open center. Connectors are often keyed to ensure the correct polarity, and may contain bumps or notches both for polarity and to ensure that the wrong type of device is not inserted. The socket's width is chosen to fit to the thickness of the connecting PCB.

In mechanical engineering, a key is a machine element used to connect a rotating machine element to a shaft. The key prevents relative rotation between the two parts and may enable torque transmission. For a key to function, the shaft and rotating machine element must have a keyway and a keyseat, which is a slot and pocket in which the key fits. The whole system is called a keyed joint. A keyed joint may allow relative axial movement between the parts.

Electrical polarity is a term used throughout industries and fields that involve electricity. There are two types of poles: positive (+) and negative (−). This represents the electrical potential at the ends of a circuit. A battery has a positive terminal and a negative terminal. Interconnection of electrical device nearly always require correct polarity to be maintained. Correct polarity is essential for the operation of vacuum tube and semiconductor devices, many electric motors, electrochemical cells, electrical instruments, and other devices.

The opposite side of the socket is often an insulation-piercing connector which is clamped onto a ribbon cable. Alternatively, the other side may be soldered to a motherboard or daughtercard.

Ribbon cable cable with many conducting wires running parallel to each other on the same flat plane

A ribbon cable is a cable with many conducting wires running parallel to each other on the same flat plane. As a result the cable is wide and flat. Its name comes from its resemblance to a piece of ribbon.

Soldering process of joining metal pieces with heated filler metal

Soldering is a process in which two or more items are joined together by melting and putting a filler metal (solder) into the joint, the filler metal having a lower melting point than the adjoining metal. Unlike welding, soldering does not involve melting the work pieces. In brazing, the work piece metal also does not melt, but the filler metal is one that melts at a higher temperature than in soldering. In the past, nearly all solders contained lead, but environmental and health concerns have increasingly dictated use of lead-free alloys for electronics and plumbing purposes.

Motherboard main printed circuit board (PCB) for a computing device

A motherboard is the main printed circuit board (PCB) found in general purpose computers and other expandable systems. It holds, and allows, communication between many of the crucial electronic components of a system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals. Unlike a backplane, a motherboard usually contains significant sub-systems such as the central processor, the chipset's input/output and memory controllers, interface connectors, and other components integrated for general purpose use and applications.


Edge connectors are commonly used in personal computers for connecting expansion cards and computer memory to the system bus. Example expansion peripheral technologies which use edge connectors include PCI, PCI Express, and AGP. Slot 1 and Slot A also used edge connectors; the processor being mounted on a card with an edge connector, instead of directly to the motherboard as before and since.

Personal computer Computer intended for use by an individual person

A personal computer (PC) is a multi-purpose computer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or technician. Unlike large costly minicomputer and mainframes, time-sharing by many people at the same time is not used with personal computers.

Expansion card a printed circuit board that can be inserted into an electrical connector, or expansion slot on a computer motherboard, backplane or riser card to add functionality to a computer system via the expansion bus

In computing, the expansion card, expansion board, adapter card or accessory card is a printed circuit board that can be inserted into an electrical connector, or expansion slot, on a computer motherboard, backplane or riser card to add functionality to a computer system via the expansion bus.

Computer memory physical device used to store information for immediate use in a digital electronic device

In computing, memory refers to a device that is used to store information for immediate use in a computer or related computer hardware device. It typically refers to semiconductor memory, specifically metal-oxide-semiconductor (MOS) memory, where data is stored within MOSFET memory cells on a silicon integrated circuit chip. The term "memory" is often synonymous with the term "primary storage". Computer memory operates at a high speed, for example random-access memory (RAM), as a distinction from storage that provides slow-to-access information but offers higher capacities. If needed, contents of the computer memory can be transferred to secondary storage; a very common way of doing this is through a memory management technique called "virtual memory". An archaic synonym for memory is store.

IBM PCs used edge connector sockets attached to ribbon cables to connect 5.25" floppy disk drives. 3.5" drives use a pin connector instead.

Video game cartridges typically take the form of a PCB with an edge connector: the socket is located within the console itself. The Nintendo Entertainment System was unusual in that it was designed to use a zero insertion force edge connector: [1] instead of the user forcing the cartridge into the socket directly, the cartridge was first placed in a bay and then mechanically lowered into position.

Nintendo Entertainment System 8-bit third-generation home video game console developed and released by Nintendo in 1985

The Nintendo Entertainment System (NES) is an 8-bit third-generation home video game console produced, released, and marketed by Nintendo. It is a remodelled export version of the company's Family Computer (FC) platform in Japan, commonly known as the Famicom, which was launched on July 15, 1983. The NES was launched in a test market of New York City on October 18, 1985, followed by Los Angeles as a second test market in February 1986, followed by Chicago and San Francisco, then other top 12 American markets, followed by a full launch across North America and some countries in Europe in September 1986, followed by Australia and other countries in Europe in 1987. Brazil saw only unlicensed clones until the official local release in 1993. In South Korea, it was packaged as the Hyundai Comboy and distributed by Hyundai Electronics which is now SK Hynix; the Comboy was released in 1989.

Zero insertion force electrical connector that requires very little force for insertion, often used for IC and CPU sockets

Zero insertion force (ZIF) is a type of IC socket or electrical connector that requires very little force for insertion. With a ZIF socket, before the IC is inserted, a lever or slider on the side of the socket is moved, pushing all the sprung contacts apart so that the IC can be inserted with very little force - generally the weight of the IC itself is sufficient and no external downward force is required. The lever is then moved back, allowing the contacts to close and grip the pins of the IC. ZIF sockets are much more expensive than standard IC sockets and also tend to take up a larger board area due to the space taken up by the lever mechanism. Therefore they are only used when there is a good reason to do so.

See also

Related Research Articles

Accelerated Graphics Port expansion bus

The Accelerated Graphics Port (AGP) was designed as a high-speed point-to-point channel for attaching a video card to a computer system, primarily to assist in the acceleration of 3D computer graphics. It was originally designed as a successor to PCI-type connections for video cards. Since 2004, AGP has been progressively phased out in favor of PCI Express (PCIe); by mid-2008, PCI Express cards dominated the market and only a few AGP models were available, with GPU manufacturers and add-in board partners eventually dropping support for the interface in favor of PCI Express.

Parallel ATA interface standard for the connection of storage devices

Parallel ATA (PATA), originally AT Attachment, is an interface standard for the connection of storage devices such as hard disk drives, floppy disk drives, and optical disc drives in computers. The standard is maintained by the X3/INCITS committee. It uses the underlying AT Attachment (ATA) and AT Attachment Packet Interface (ATAPI) standards.

Backplane PCB containing connectors for daughterboards electrically linked pin-by-pin

A backplane is a group of electrical connectors in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors, forming a computer bus. It is used as a backbone to connect several printed circuit boards together to make up a complete computer system. Backplanes commonly use a printed circuit board, but wire-wrapped backplanes have also been used in minicomputers and high-reliability applications.

Bus (computing) communication system that transfers data between components inside a computer

In computer architecture, a bus is a communication system that transfers data between components inside a computer, or between computers. This expression covers all related hardware components and software, including communication protocols.

Industry Standard Architecture 16-bit internal bus of IBM PC/AT

Industry Standard Architecture (ISA) is the 16-bit internal bus of IBM PC/AT and similar computers based on the Intel 80286 and its immediate successors during the 1980s. The bus was (largely) backward compatible with the 8-bit bus of the 8088-based IBM PC, including the IBM PC/XT as well as IBM PC compatibles.

Conventional PCI local computer bus for attaching hardware devices

Conventional PCI, often shortened to PCI, is a local computer bus for attaching hardware devices in a computer. PCI is an abbreviation for Peripheral Component Interconnect and is part of the PCI Local Bus standard. The PCI bus supports the functions found on a processor bus but in a standardized format that is independent of any particular processor's native bus. Devices connected to the PCI bus appear to a bus master to be connected directly to its own bus and are assigned addresses in the processor's address space. It is a parallel bus, synchronous to a single bus clock.

VESA Local Bus VESA Local Bus

The VESA Local Bus was a short-lived expansion bus introduced during the i486 generation of x86 IBM-compatible personal computers. Created by VESA, the VESA Local Bus worked alongside the then dominant ISA bus to provide a standardized high-speed conduit intended primarily to accelerate video (graphics) operations. VLB provided a standardized "fast path" that add-in (video) card makers could tap for greatly accelerated memory-mapped I/O and DMA, while still using the familiar ISA bus to handle basic device duties such as interrupts and port-mapped I/O.

Tandy 1000

The Tandy 1000 was the first in a line of IBM PC compatible home computer systems produced by the Tandy Corporation for sale in its Radio Shack and Radio Shack Computer Center chains of stores.

PC Card expansion card standard for laptop computers

In computing, PC Card is a configuration for computer parallel communication peripheral interface, designed for laptop computers. Originally introduced as PCMCIA, the PC Card standard as well as its successors like CardBus were defined and developed by the Personal Computer Memory Card International Association (PCMCIA).

Serial ATA computer bus interface for storage devices

Serial ATA is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PATA) standard to become the predominant interface for storage devices.

Single-board computer complete computer built on a single circuit board

A single-board computer (SBC) is a complete computer built on a single circuit board, with microprocessor(s), memory, input/output (I/O) and other features required of a functional computer. Single-board computers were made as demonstration or development systems, for educational systems, or for use as embedded computer controllers. Many types of home computers or portable computers integrate all their functions onto a single printed circuit board.

ATX Motherboard and power supply configuration

ATX is a motherboard and power supply configuration specification developed by Intel in 1995 to improve on previous de facto standards like the AT design. It was the first major change in desktop computer enclosure, motherboard and power supply design in many years, improving standardization and interchangeability of parts. The specification defines the key mechanical dimensions, mounting point, I/O panel, power and connector interfaces between a computer case, a motherboard and a power supply.

D-subminiature type of electrical connector

The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems.

Slot 1

Slot 1 refers to the physical and electrical specification for the connector used by some of Intel's microprocessors, including the Pentium Pro, Celeron, Pentium II and the Pentium III. Both single and dual processor configurations were implemented.

The Advanced Communications Riser, or ACR, is a form factor and technical specification for PC motherboard expansion slots. It is meant as a supplement to PCI slots, a replacement for Audio/modem riser (AMR) slots, and a competitor and alternative to Communications and Networking Riser (CNR) slots.

M.2 form factor for solid-state disks and miniature expansion cards

M.2, formerly known as the Next Generation Form Factor (NGFF), is a specification for internally mounted computer expansion cards and associated connectors. M.2 replaces the mSATA standard, which uses the PCI Express Mini Card physical card layout and connectors. Employing a more flexible physical specification, the M.2 allows different module widths and lengths, and, paired with the availability of more advanced interfacing features, makes the M.2 more suitable than mSATA in general for solid-state storage applications, and particularly in smaller devices such as ultrabooks and tablets.


  1. "Lance Barr Interview". Nintendo News, Previews, Reviews, Editorials and Interaction. Nintendojo.com. Archived from the original on 13 March 2012. Retrieved 20 October 2011.