Small Engines (Lawn Mowers, etc.): small engine electrical system, rectifer, electricity generation

Question
Hello, I have a question about the charging systen in lawn tractor and how they work. Do they use a small alternator? To check the battery charged. Or on snowblowers how do you get power for the light. These questions are just to find the general operation of snall engine electricity generation of another applications. Thank you for your help. Tony

Answer
Most small engines use a small alternator.  As the flywheel rotates, the magnets rotate past the alternator generating AC current.  To charge the battery the AC is converted to DC using a diode.  Fancier systems use a full wave rectifer and a regulator.   

Most lighting systems operate on the AC circuit.  As the engine speeds up more AC current is generated which is why the lights get brighter with engine speed and dimmer when the engine slows down.  Again, fancier systems use a regulator and DC current to provide a constant brightness.

Does this help?
Let me know.
Eric