The Hall Effect

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <882565FA.00538089.00@fcpa_nt6.fcpa.fujitsu.com> "Matt Rooke" writes:

> Umm, good try, and maybe more appropriate than the right answer...

> The Hall effect is what happens when you move a magnet past a properly aligned electrical coil- you get a voltage at the
> terminals of the coil.  Now if that magnet is attached to a rotating shaft, you can measure the speed of the shaft
> rotation by the frequency of the electrical pulses from the coil.

But this is _not_ the right answer - there's no coil in a Hall sensor.

A Hall sensor is a piece of semiconductor through which a current is
passed.  Think of something the shape of a football field, with electrons
flowing between the goals.  If a magnetic field appears, perpendicular
to the surface, those electrons are going to miss the goal and perhaps even
leave the field by the side lines.  Which is where a Hall sensor has
'sensing' electrodes.

--
 Phil Payne
 Phone: 0385 302803   Fax: 01536 723021
 (The contents of this post will _NOT_ appear in the UK Newsletter.)