Questions about connection quality

[SoaDMTGguy]

First I want to state that I'm only concerned about electrical connection quality, for the sake of this argument assume mechanical connection quality is irrelevant.

I have read that a soldered connection is always best (which makes sense). But what is less clear to me is how much *worse* other types of connections are. For example, friction-based "quick disconnect" tabs, or screw-down terminals.

For that matter, how much does an extra solder joint affect the connection? How different is a single cable vs. two cables soldered together?

Or, lets say you have an IC with a broken leg. You solder a new leg on as a patch. Have you quantifiably degraded the performance of the circuit?

 

[JMFahey]

lets say you have an IC with a broken leg. You solder a new leg on as a patch. Have you quantifiably degraded the performance of the circuit?

Not at all.

That leg will lead to some kind of semiconductor inside.
It´s own resistance or even worse,voltage drop, will be orders of magnitude higher than the soldered connection added microohms.

Because I´m not sure it even reaches milliohms, go figure.

And even if it did .....

 

[Mark Tillotson]

Crimping is supposed to be far better than soldering for longevity as it introduces less stress-concentration. In high vibration environments the point in a stranded wire where the solder ends is where failures occur. But a crimp joint has to be done properly, with the right tool, to be fully reliable.

I believe wire-wrap was supposed to beat soldering for reliability too.

Anyway the place to look for what is good is in standards for avionics I suspect.