SE fellas

Today I was thinking about electrolytic capacitors. it's a question to me Why some electrolytic capacitors have(or manufacturers make) a bigger distance between their two legs? I'm talking about this:


While other is like this:

enter image description here

I doubt if it would have relation to electrolytic capacitors production line. I guess there is a specific reason for an EE.

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    \$\begingroup\$ Probably to force you to solder as it should (with a space between the electrolytic capacitor and the board for better air circulation). E capacitors are very sensible to temperature changes, which affect their capacitance. \$\endgroup\$ Sep 23, 2015 at 17:00
  • \$\begingroup\$ @PedroQuadros Maybe/Probably you are right. I heared it though. \$\endgroup\$
    – Roh
    Sep 23, 2015 at 17:02
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    \$\begingroup\$ I honestly don't know but maybe those legs bent like that will hold it up off the board just enough that it can later be bent flat after wave? \$\endgroup\$ Sep 23, 2015 at 17:02
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    \$\begingroup\$ I guess they are trying to match some standard pitch.. \$\endgroup\$
    – Eugene Sh.
    Sep 23, 2015 at 17:03
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    \$\begingroup\$ The bent ones stick better to the PCB when you stick them into the board, but that is really only an advantage when hand soldering. \$\endgroup\$
    – jippie
    Sep 23, 2015 at 17:50

2 Answers 2


Every year they seem to figure out ways of making e-caps smaller and smaller so at some point forming the leads is required to fit the pattern of the old capacitors.

Changing hole layout of high volume inexpensive boards can involve changing hard tooling (punch positions in the die) rather than the soft changes that are typical for low-volume and high-end boards.

The suppliers can provide parts on tape with the leads formed to the customer's requirements.

  • \$\begingroup\$ It's a bit funny to me but makes sense to me. Thanks for answer. \$\endgroup\$
    – Roh
    Sep 23, 2015 at 17:18
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    \$\begingroup\$ It's not just electrolytics. I have seen the same on through hole MMC and small signal transistors too. \$\endgroup\$
    – BenG
    Sep 23, 2015 at 20:45
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    \$\begingroup\$ The pin spacing on TO92s is too tight to be directly inserted (in most cases) so you can buy them on tape (ammo pack) with leads formed (or in bulk and form them in a machine). \$\endgroup\$ Sep 23, 2015 at 20:54

Those indents, or bends make it so the part is lifted above the PCB, (through hole), make it so the component has some room for air flow. Or that was the explanation I received when I asked the same question about 10 years ago.

Straight through leads you could optionally bend to put in the gap for air flow.

Other manufacturing differences can make size variations in capacitors including dielectric material, plate material, gauge specifications, etc... for any given set of capacitors, at a given capacitance, thermal rating, and voltage rating.

Electrolytic Capacitors are not the only devices that will come with the crimps in leads. I have seen fuses, Mylar and ceramic capacitors, transistors, and resonators, with factory crimped leads.

I'd be willing to bet the 1/2 second it takes to crimp the leads saves manufacturers money to omit.

I can take some photos of in-circuit parts like this, if you like.

As @Spehro Pefhany suggests, you will likely see lest of this in the future, as through hole components disappear.

  • 1
    \$\begingroup\$ There may also be a standard spacing, for Throught hole components placement. I thought of this, when i considered that most every through hole component fits into a bread board, and that prototyping PCBs are all fixed width. I’ve never measured that distance, and probably ignored every detail on lead spacing I have ever read. Perhaps components are bent to conform to a spacing standard. IDK \$\endgroup\$
    – j0h
    Sep 24, 2015 at 11:28

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