mechanical computation: with Merkle gates, height fields,
dave.long at bluewin.ch
Fri Jul 2 09:49:55 EDT 2010
Le 28 juin 10 à 09:37, Kragen Javier Sitaker a écrit :
> But braking can provide amplification. Imagine that you have a thread
> running along the surface of a cylinder; it can slide freely, as far
> as it as long as no force presses it against the cylinder. If another
> thread is wrapped loosely several times around the cylinder and the
> sliding thread, the sliding thread can still slide; but if the wrapped
> thread is then pulled taut, it presses the sliding thread against the
> cylinder, preventing it from sliding.
if the cylinder is externally powered, a single thread suffices; when
it is wrapped loosely no power is coupled, but a little tension on
the input side produces a lot on the output side.
cf differential analyzers (previous century) and capstans (previous
millenium) Friction-effect transhawsers?
(early automated feedback applications were for windmills; I wouldn't
be surprised if the separation of power and control had also been
useful relatively early for animal-driven milling...)
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