Circuit for noise suppression in a ignition system of a vehicle

The circuit has a supply voltage connection for connecting to a first terminal of a d.c. source, an earth connection for connecting to the second terminal and an ignition transformer with a primary winding with ends connected to the supply voltage connection and via a current switch element to the second d.c. source terminal. The first primary winding end is connected to the earth connection via two opposite polarity Zener diodes in series. The circuit arrangement has a supply voltage connection for connecting to a first terminal of a d.c. source (10), an earth connection (8) for connection to the second terminal and an ignition transformer (1) with a primary winding (2) with ends connected to the supply voltage connection and via a current switch element (4) to the second terminal of the d.c. source. The first winding end of the primary winding is connected to the earth connection via a protective series circuit (5) of two opposite polarity Zener diodes.