While working on a project recently, I noticed that Digi-key has a product category "Terminals - Turret Connectors". I've never seen connectors like this before, and they don't look like any kind of contact I've seen before. What does the mating connector look like? I can't envision any mating contact that makes any sense for these.

On top of that, they look like they have to be individually machined, which can't be a cost-effective process.

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  • \$\begingroup\$ There is no mating connector, you just wrap a wire around it and solder it on. \$\endgroup\$ – The Photon Mar 10 '19 at 16:44
  • \$\begingroup\$ @ThePhoton So these are more for point-to-point construction I guess? \$\endgroup\$ – Hearth Mar 10 '19 at 16:45
  • \$\begingroup\$ You still find them on some RF modules. For example, some LNAs by Minicircuits. \$\endgroup\$ – Marcus Müller Mar 10 '19 at 16:47
  • \$\begingroup\$ I used to use them for a ground connection for probes since they're larger than a Keystone 5019 and can accommodate multiple connections easier. \$\endgroup\$ – Matt Young Mar 10 '19 at 17:04

Turret connectors or more commonly Turret terminals are used for to make interconnections between PCB and chassis-mounted components.

Basically these are metal terminals to which wires are connected in a U shape and then soldered to provide strong and reliable connections.

The turret refers to the amount of levels (i.e. the disk like separations) the terminal has. These terminals commonly come in the following types but custom terminals can also be made.

  • Single Turret
  • Double Turret
  • Triple Turret
  • \$\begingroup\$ So what makes these better than just soldering directly to the board? \$\endgroup\$ – Hearth Mar 10 '19 at 17:00
  • \$\begingroup\$ Incidentally, sorry to mess up your 1337 reputation score with my upvote! \$\endgroup\$ – Hearth Mar 10 '19 at 17:00
  • \$\begingroup\$ @Hearth, From the images I found online, I concluded that these terminals were most commonly used on panels instead of PCBs. Hope this helps but a person of that era might be able to explain this better. \$\endgroup\$ – Electric_90 Mar 10 '19 at 17:07
  • \$\begingroup\$ I didn't knew the meaning of 1337, googled it right now. No problem always appreciate an up-vote :) \$\endgroup\$ – Electric_90 Mar 10 '19 at 17:11
  • \$\begingroup\$ @Hearth, Take a look here, seeing this page, I suspect that turret might be a better option over a straight away connection as directly soldering low-gauge wire might end up ripping the copper layer. Also, joining multiple wires is a lot easier with the help of turret. \$\endgroup\$ – Electric_90 Mar 10 '19 at 17:27

We used them in the 70's for pigtail wire soldering and they are swaged or press fit onto PCBs. Not expensive. They used to be a penny in volume now $0.07. That's inflation and dates me.

The purpose is to provide a strong mechanical joint for stranded wires with 1 wrap around the turret and potted to NASA standards for reliability for strain relief.

This article explains some of the science and MTBF calculations behind moving wire fatigue which is consistent with my experience in production and reliability testing.

Whereas a wire soldered directly to the board lacks the strain relief at the interface. Of course, commercial practice has alternatives, suboptimal, but adequate in their environment.

  • \$\begingroup\$ Well now I'm curious how they managed to manufacture them so cheaply, as the shape looks like it has to be machined on a lathe... or are they cast in molds somehow? Those protrusions combined with the bottom part apparently being hollow makes them seem kind of complex to manufacture. \$\endgroup\$ – Hearth Mar 10 '19 at 16:52
  • \$\begingroup\$ Well that's a trade secret, but the cheaper ones are roll hardened CuZn (brass) then annealed or softened to make less brittle then tin plated. I have a retired friend who used to machine the gold connector threaded parts in large batches in the last decade for tidy profits for ARINC-B connectors that made these parts look massive. \$\endgroup\$ – Tony Stewart EE75 Mar 10 '19 at 17:06
  • \$\begingroup\$ Our techs had NASA soldering manuals thicker than the bible and koran put together. imagine that. These included photos of idea pigtail solder joints for 10 lb pull tests on wires. But being hard brass, they still bend before breaking. THe wires soldered in PCB's have a discontinuity in stress/strain making them prone to vibration failures. ( do I need to explain that?) \$\endgroup\$ – Tony Stewart EE75 Mar 10 '19 at 17:08
  • \$\begingroup\$ @SunnyskyguyEE75, found this page which relates to the things you have mentioned. \$\endgroup\$ – Electric_90 Mar 10 '19 at 17:21
  • \$\begingroup\$ You can reduce the solder stress discontinuity on stranded wires by allowing the solder to wick up the insulation at least 5x diameter of wire thus creating a stiffer bond and tie wrapping with a large bend radius so that wire vibration in is a semi-circle and moves axially more than radial by design. This makes it survive harsh vibration > 1million cycles at some f. I used to test this in some products and learnt how it is done. So often braided wire breaks due to lack of strain relief in consumer products poorly designed. \$\endgroup\$ – Tony Stewart EE75 Mar 10 '19 at 17:25

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