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When designing a PCB, it's common to place pads as test points. What about ground for test? Should I just place a pad connected to ground? The problem is that it's hard to manually hold probes to two different points at once.

Is there a way to design the ground pads so they can be more easily gripped with clips or the like? Perhaps drill holes? (I know there are also protruding loops that can be soldered on, but my fabricator does not stock those.)


Update

This questions is not a duplicate of What probe/tip to use to clip into a PCB test point? . That asks: "Given a PCB, what probe should I use to contact ground?". However, this question asks "I'm designed a PCB. How can I design it so that it easy to hook to ground for test." This is a "Design for Test" question.

Someone mentioned adding the Keystone loops. As the original question mentions, I'm aware these exist, but they are not available at the assembler. So, this question is "Given the unavailability of special components, such as protruding loops, what PCB features, such as pads, holes, or tracks, can be done to design and fabricate the PCB to support connecting it to ground for test."

Given the above, I ask that the question be reopened.

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    \$\begingroup\$ Also this worth a look: What is the part name / description for these test points? \$\endgroup\$ Commented Sep 11, 2023 at 17:59
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    \$\begingroup\$ Then there's also the single pin of 0.1" pin header option. \$\endgroup\$ Commented Sep 11, 2023 at 18:01
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    \$\begingroup\$ I would enjoy reading the answer(s) to this question from experienced manufacturers. I often see a lot of testpoints but rarely a place to put your ground clip or those low-inductance spiral ground probe adapters \$\endgroup\$
    – pipe
    Commented Sep 12, 2023 at 14:18
  • \$\begingroup\$ Well, there's a range of possible answers. "Experienced manufacturers" will have such parts available. They'll also have bed-of-nails testers in production, for which plain SMT pads of adequate size and spacing will do. But is that useful enough to the OP? Are you doing one-offs, hand prototypes, etc.? Also, you can always add parts after manufacture, nothing's stopping you from using the soldering iron at any time; does that change your calculus at all? \$\endgroup\$ Commented Sep 12, 2023 at 15:10

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Just add a single 0.1 pin header as @Tom Carpenter said. Or if you plan to do a lot of testing, add a 0.1 pin header strip with all test pins side by side. You could choose not to populate this component in production, and easily populate it by hand for prototypes.

With such a header strip, you could easily build a test cable with all your test points pre-connected to the desired test equipment. Then it's easy to plug the test header onto the board, read the results, and move on. No fiddling about with probes required!

For a bit more insulation against accidental shorting of the test pins, install the female 0.1 header socket on the board, and use the male headers on your test cable.

Note that if you are testing high-frequency lines, adding a connector may introduce unwanted capacitance, so be sure to take this into account.

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Is there a way to design the ground pads so they can be more easily gripped with clips or the like? Perhaps drill holes?

Plated through hole connecting a ground pad to the ground plane can make it a lot easier to use spring clips for probing, especially for high frequencies. They're less likely to slide off if you have a hole to catch them, and no special components are required.

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  • \$\begingroup\$ Is "plated through hole" the same thing as a via? If not, what is the difference? Also, if I'm connecting my clip to the hole, why do I need a ground pad - can't I just clip to the hole? \$\endgroup\$ Commented Sep 12, 2023 at 17:57
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    \$\begingroup\$ @SRobertJames Basically a larger diameter via, yes. You could put just the hole if you wanted, but having the pad there is nice too in case you decide to solder to it and because it gives you a bit more surface area to contact. \$\endgroup\$ Commented Sep 12, 2023 at 18:47

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