The Electrical System of a car consists of a battery, alternator starter motor distributor lighting system (includes head and tail lights.stop lights turning lights dash lights )
Everything starts with the battery which holds the electrical charge for the vehicle.
The starter motor turns on the motor when the ignition switch is activated usually with a key.
The distributor sends a high voltage current to the spark plugs in the correct firing order.
The engine runs
Lights take their power from the battery
When the engine is running the alternator which is connected to the engine with a drive belt then recharges the battery
This is a simplistic explanation of how the closed electrical circuit system works.
Any of these electrical components can fail or work less efficiently.
Regular servicing will quite ofter prevent a failure and the inconvenience that occurs.
Ro keep your vehicle’s electrical running smoothly,,,,