Electrical systems in light aircraft
Typically light normal category aircraft make use of either a 14 VDC or 28 VDC electrical systems powered primarily by an engine driven alternator. This provides power to one or more power bus bars which provide electrical power to the various aircraft systems requiring it.  Below is an example light aircraft electrical system from a Cessna 172S.





One notable deviation from automobile electrical systems is that the engine spark plugs receive electricity from a separate pair of magnetos which produce their power independent of the main electrical system for reasons of redundancy.