An edge connector or card edge connector is a female socket which mates directly with the edge part of single or double-sided PCB (Printed Circuit Board). The edge of the PCB has metallic tracks on it that engage with the contacts in the socket to provide an external electrical connection. In this way, the edge of the PCB acts as a male connector. The connector is held in place by the friction between the board and the socket

Features of an Edge Connector

Housings: The female edge connector consists of a plastic housing which has an opening on one side into which the edge of the PCB is inserted. Edge connector socket housings are often keyed to ensure that they are used the right way up preventing assembly error. Notches or bumps on the housing help to prevent an incorrect device from being inserted
Contacts: Inside the edge connector housing are contacts which connect with the metal traces on the edge of the PCB on insertion. The contacts are made of metal with a thin metallic plating that improves conductivity and prevents rust and corrosion
Termination Types: Edge connectors with IDC contacts can be terminated directly onto ribbon cable. Edge connectors with pins are soldered onto a PCB.

Variations

Edge connectors vary in terms of the following:

Rows: Edge connectors are available with one or 2 rows of contacts
Pitch: Edge connectors are available with a range of contact pitches
Number of Contacts: Edge connectors are available with different numbers of contacts
Orientation: Edge connectors are available with a vertical or right angle mounting orientation.

Where are edge connectors used?

Edge connectors are commonly used in personal computers for connecting expansion cards or daughtercards and computer memory to the motherboard. These expansion cards include PCI, PCI Express and AGP cards