Talk:Edge connector

Earliest?

There appear to be some pretty standard edge connectors out there, or were before PC computers came along at any rate, mostly varying according to the number of contacts and their spacing. The 44-pin example shown on the edge connector page had to be the most common type, but there were many other variants. One that I can recall is a 22-pin single-sided version of that one, and there were others. Spacing of the connectors was another variant besides the number of pins. I believe I can remember 0.100", 0.125", and 0.156" variants, and there were no doubt others. I'm not clear on what the versions are that came out later on with PC computer hardware and those used in RAM sockets, but perhaps some mention of these ought to be included in here also.

Rtellason (talk) 02:09, 15 April 2009 (UTC)Roy J. Tellason, Sr.

I am wondering about the history of them. Does anyone have a time-table of when they were invented, various patents, etc.? 73.181.82.26 (talk) 19:51, 25 October 2015 (UTC)

PCB thickness and edge connector

As an edge connector's thickness equals its PCB's thickness, it is obvious that the overall PCB design (number of layers, ground planes etc.) affects the design constraints of an edge connector.

• What happens if a PCB design is too thin for its edge connector to fit in a mating socket? Is it possible to add "empty buffer layers" to fill up the PCB?
• What about the opposite case - a PCB already too thick to have its edge connector fit in the socket?

Thanks for ideas, --Abdull (talk) 19:42, 14 May 2010 (UTC)

The overall PCB layer stackup design is irrelevant to the design of the edge connector. No matter what the number of layers, number of ground planes, etc., practically all PCBs end up at 1/16 inch thick (1.58 mm thick). (See Wikibooks:Practical Electronics/PCB Layout#Board Thickness and Layers).

As you have already guessed, the people who make the bare PCB often start with much thinner laminates and glue "empty buffer layers" in the middle to fill it out to the full 1/16 inch thickness.

Every edge connector socket I've ever seen is designed to accept boards 1/16 inch thick. (The spring-loaded contacts in the socket have some tolerance for variations in thickness from one board to another).

Today the cause-and-effect flows both directions -- we have a network effect where people designing edge connector sockets, and people designing boards to plug into such sockets, all use the same size. Some other size would probably have worked just as well, but because of historical inertia, we're stuck with 1/16 inch thick. Also, because boards that plug into such sockets are manufactured in such huge numbers, economies of scale make boards manufactured to that thickness cost slightly less than boards manufactured to some other "special" thickness -- so people designing PCBs that don't have any particular thickness requirement also end up with boards of that thickness, leading to more historical inertia.

How can we make the edge connector and printed circuit board articles more clear on these issues? --DavidCary (talk) 17:44, 30 August 2013 (UTC)

History

The article definitely needs expansion, as it's essentially an extended dictionary entry sans linguistic information. What is the origin of edge connectors? What variations have existed? When did edge connectors first appear and for what application? -- 173.74.67.97 (talk) 16:46, 22 April 2015 (UTC)