William M. Gilroy wrote:
>
> Rick Morrison wrote:
> >
> >
> > same time, 180 degrees apart (crankshaft rotation) with one being a
> > "wasted" spark on the exhaust stroke, the number of sensor points (either
> > magnetic, hall effect or optical) is reduced by half and allows the
> > sensor to be driven by the crankshaft, instead of the camshaft, if each
>
> What is the "hall effect" ?
>
> --
> William M. Gilroy
> 77 Midget
> E-mail: wmgilroy@lucent.com
> Telephone: 732-957-4775
> Fax: 732-957-4775
The 'Hall Effect' is the name given to the principle discovered by a
chap called, oddly enough, Dr. Hall. It is used in distributors that
have a chopper-plate inside instead of points, switching on and off the
magnetic field, by alternately covering and uncovering the Hall chip, (
a crystal.)
Back at school years ago, you used it to decide which way a current
flowed along a wire. The magnetic effect produced around the cable
whilst current is flowing is proportional to the currents value.
The other ' optical' system used a LED opposite a photo-diode, and a
similar 'chopper' plate switches it on and off.
Both are ideal for modern Engine Management systems, for both ignition
and other items that need a clear signal.
Neil.
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