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It seems most solderless breadboards don't have the connection points on the power rails aligned to the rest of the connection points.

Some just omit every 6th; on some the gap isn't even a multiple of 0.1 inches so some points don't line up at all.

I think for some usual applications it would be convenient if the power rails were aligned to the rest of the board. For example, to connect one side of a DIP-switch or bar graph LED to one of the rails all at once.

Is there a practical reason for this misalignment?

photo of a solderless breadboard showing non-aligned connection pins

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    \$\begingroup\$ no, there is no reason, other than bad design and copying a bad design \$\endgroup\$
    – jsotola
    Jan 5 at 21:11
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    \$\begingroup\$ Well the practical reason is that it doesn't matter since there are no ICs that would fit even if they were aligned. \$\endgroup\$
    – DKNguyen
    Jan 5 at 21:21
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    \$\begingroup\$ The spacing varies by manufacturer, some line up, some don't. \$\endgroup\$
    – GodJihyo
    Jan 5 at 22:06
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    \$\begingroup\$ I've never seen breadboards like this. All my breadboards are aligned. It would drive me crazy if I can't tidy up my wiring because the power rails are misaligned. And they're not even misaligned a reasonable angle like 45 degrees! That's like what.. 22 degrees or something? \$\endgroup\$
    – slebetman
    Jan 6 at 6:30
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    \$\begingroup\$ Anecdotal I know, but I've never seen a breadboard where the power rail holes didn't line up with the working area. Maybe get a new breadboard.... \$\endgroup\$
    – Kyle B
    Jan 6 at 19:18

4 Answers 4

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The contacts are manufactured in strips with a space between every 5 where they cut them apart to make the main contacts, then they use the same strips for the power rails and cut them to whatever length they need for the size of breadboard.

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  • \$\begingroup\$ I see… too bad the "practical" aspect is on the producers side - had some hope for "hidden feature" for users ^^ \$\endgroup\$
    – kai-dj
    Jan 5 at 21:22
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    \$\begingroup\$ One mine at least, the space maintains separation, so there's simply a missing hole. That means still only blocks of 5 holes but at least they line up \$\endgroup\$
    – Chris H
    Jan 6 at 14:38
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    \$\begingroup\$ Yes. But some (judging by online listings i saw many) gaps are not sized in multiples of 0.1 inches. Also the limit of 5 connection points rules out many components (e.g. the bar graph led blocks which sparked the Q for me). \$\endgroup\$
    – kai-dj
    Jan 7 at 7:53
  • \$\begingroup\$ Everyone who has an old beat-up power-surge-singed breadboard socket should take it apart and look at the metal strips with finger contacts. \$\endgroup\$
    – DarenW
    Jan 11 at 4:06
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So some amateur doesn't try to insert an IC between the working area and the power rail. It was done on purpose.

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  • \$\begingroup\$ Somewhat reasonable. Still… i would prefer a fried IC (and having learned something ^^) over the misalignment and connecting manny pins to the same rail separately for each pin for each bar graph for the rest of my life ;) \$\endgroup\$
    – kai-dj
    Jan 5 at 21:36
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    \$\begingroup\$ Maybe there is a missed opportunity out there for a new design. No rules prevent you from launching a new product. I heard there are a bunch of empty booths at CES2022 if you can get it done for a New product launch by Friday in Vegas. \$\endgroup\$ Jan 5 at 21:49
  • \$\begingroup\$ XD will not fly to vegas… Also don't see my future in producing better breadboards (not friday, not in the long run). \$\endgroup\$
    – kai-dj
    Jan 5 at 21:52
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    \$\begingroup\$ @GodJihyo, you said, "Breadboards were originally designed for engineers anyway, so there would be some expectation of competence". First, that's funny because I make things idiot-proof for engineers and technicians every day. One example would be the alarm on a fluke hand-held meter when you switch to volts when you still have the cables plugged into the amps port. That alarm is not for the general public, it is on a $400 meter for professionals. And, breadboarding in my facility is typically done by technicians. Any engineer adjusting designs over a breadboard gets ridiculed. \$\endgroup\$ Jan 5 at 23:45
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    \$\begingroup\$ @GTElectronics, do you have a source on the claim that it was done on purpose? A statement from an early designer, for example. Or is this just post-facto rationalization? \$\endgroup\$
    – ilkkachu
    Jan 6 at 15:08
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The gaps are for tabs that hold the metal rails to the plastic, so that they don't come apart.

Removing the back of a breadboard shows the structure. On some breadboards the back is glued and removing it will damage it, but here is a picture courtesy of Sparkfun tutorial:

Breadboard backside

As can be seen, the metal is continuous but there are small spikes that go into plastic to hold it in place.

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    \$\begingroup\$ Those aren't really tabs holding the strips in place, they're just a flattened part of the strip. The metal strip is bent in a U where the contacts are, with these little flat parts in between where they're going to cut them (makes it easier to cut without deforming them). The contacts in the holes are more than enough to hold them in place. \$\endgroup\$
    – GodJihyo
    Jan 7 at 14:34
  • \$\begingroup\$ @GodJihyo Hmm, after watching some youtube videos, I think you are right! \$\endgroup\$
    – jpa
    Jan 7 at 18:08
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It seems most solderless breadboards don't have the connection points on the power rails aligned to the rest of the connection points.

This is not true of all solderless breadboards.

enter image description here

K & H AD-102 Advanced Solderless Breadboard - 456 Tie Points

As others have said, the gaps in the power rail tie-points appear to be simply a manufacturing convenience.

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    \$\begingroup\$ Well they are aligned - but the power rails have gaps… \$\endgroup\$
    – kai-dj
    Jan 7 at 7:45
  • \$\begingroup\$ Two missing holes, not just one? I've not seen that before, and I've been using breadboard of this general nature since high school, (mumble) decades ago. Always one missing hole, due to the how the metal strip underneath is made. \$\endgroup\$
    – DarenW
    Jan 11 at 4:10

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