A few models have free turning mouse wheels, but why do most mouse wheels have a notched mechanism?

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    When used for text scrolling, you can configure the number of lines per notch. – AFH Oct 28 '18 at 16:35
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    The only true factual basis for answering would be things like involvement on the design team, documentation of the design decision, review of the patent application. or documentation of the feature in marketing materials. None of those are likely to be the basis for answers here. So while it could potentially attract a correct answer, it would be tough to validate, and it is likely to attract mostly speculation and opinion. – fixer1234 Oct 28 '18 at 23:37

The original mice with wheels from the 1980s were "freewheeling" and highly annoying.

Once you had scrolled the document to where you wanted, you'd let go of the wheel and—invariably—the document would jump up or down a little bit (for example, a few lines) as you released. So then you'd try to move it back to where you wanted and carefully release and it might still jump a bit.

Someone brilliantly figured out that adding a detent (like quality car stereos) completely solved the problem. This was such an easy and obvious solution that it is widely used.

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  • Unless you can provide details as to pretty much all of the claims you are making, this is all speculative. – Giacomo1968 Oct 28 '18 at 16:39
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    Kind of... but early mouse wheels were based on the analog movement of small rollers, now they're optical & register scroll by how many 'holes' it passed. The click is almost a byproduct of that [though not physically connected]. Also cheap mice were always rubbish & would give poor results... things don't change there. – Tetsujin Oct 28 '18 at 16:39
  • @JakeGould: You want more details to make my first-person account non-speculative?! – wallyk Oct 28 '18 at 18:54
  • @wallyk “You want more details to make my first-person account non-speculative?!” Yes! Your “first-person” account provides no makes, models or design decisions. It’ll based on nothing more than utterly nothing. Tetsujin’s description in his comment provides more mechanical details that your answer does. – Giacomo1968 Oct 28 '18 at 22:28

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