It consists of two parts (written and oral). The written part is mandatory for everyone and covers topics dealt with during the course.
From this written part you can get up to 40 points, minimum required is 10 points. If a student gets less than 10 points will automatically fail the whole exam (in the current term), even though the sum of points together with points from labs would be over 50.
If a student reaches from 10 to 19 points, then the oral part is obligatory. At the oral exam can receive up to 10 additional points. In sum, however, must get at least 20 points.
For students with 20 and more points from the written part is the oral part voluntary.
Oral exam aims to providing additional explanation from written part. The overal rating can be both improved, and worsened.