при вращении "зубцы" индуцируют импульсы во внешней обмотке.


http://niva.noteclub.ru/tehnika/elektro/zazhig/zazh213.htm

http://www.fourforty.com/techstuff/ignition.html

http://www.proz.com/?sp=h&id=152665

http://www.autosite.com/garage/subsys/09-04d.asp

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Note added at 1 hr 33 mins (2004-12-25 15:03:33 GMT)
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http://www.autosite.com/garage/subsys/09-05d.asp

> With the reluctor high points out of alignment with the pickup coil, a wide gap and a weak magnetic field exist between the reluctor high points and the pickup coil.


http://www.autosite.com/garage/subsys/09-06d.asp

> When the reluctor point is aligned with the pickup coil, the pickup gap is narrower and the magnetic field is stronger.