Choosing the "right" connectors?


I’m not sure where to post this “generic” question but it is related to layout due to the footprint being used…

I always find it difficult to select the “correct” connectors for my external wiring and I ended up usually using 3.5mm or 5mm terminal blocks ( or screw terminals ) or just male pin header …

There are like gazillion of connectors with all shapes and sizes out there…

Any suggested reading materials or links on how to improve my choices of external connectors ??

Do you buy many sample connectors for this purpose of selection ??

I saw a book from WE called Trilogy of Connectors

Is this a recommended book ?



The correct connector highly depends on your usecase, your budged and the infrastructure you have in place.

A few things to consider:

  • availability
  • electrical parameters (nominal voltage and current, for rf also the nominal impedance)
  • how is the wire connected to the plug? (screw terminal or spring, solder, crimp)
    • Remember: crimp connectors might require quite expensive tools.
  • mechanical side: do you require locking, keying, …
  • how much space is available? (on the board, also outside the board)
  • surface mount or through hole? (manual assembly or do you want to use a pick and place machine?)
  • if you want panel mount connectors you might additionally want it to be waterproof.


Connectors are important, and often overlooked. It seems like we spent 30% of the project time discussing connectors! Maybe we don’t spend enough, because a good proportion of field failures are due to problems with connectors.

There are so many factors involved, apart from the obvious current/voltage rating, it is impossible to give generic advice. For example, environmental factors can be huge. Equipment that runs fine in a clean room turns out to run not so well in a blast furnace… Whether the connector mated once at assembly, occasionally by qualified service personnel, or frequently by unskilled customers is a big factor. And of course underlying all decisions is cost.

I would also be interested to know of any recommended reading, most of the info I get is from vendors, who obviously all claim their connector series is the best.


Add to @Rene_Poschl list type approval and legal requirements

AC mains connectors have very specific rules in most countries and anything requiring high voltage isolation needs creepage and clearance to be thought out


This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.