Polarity reversal protection circuit for external source driven-starting pole in motor vehicle, has switching control element opening switching element when electrical supply is switched off by electrical system

摘要

The circuit (10) has a switching element (6') arranged between a switching control element (4) and another switching element (6). The control element is connected with a mass by the element (6) in a closed condition. Another switching control element (7') closes the element (6') when the element (7') is electrically supplied from an electrical system (2). A third switching element (3) is closed and the element (7') opens the element (6') when electrical supply is switched off by the electrical system. An independent claim is also included for a method for providing a polarity reversal protection for an external source driven-starting pole in a motor vehicle.