Method for modelling a component fault tree for an electric circuit, - in which the electric circuit has at least one input-side (A, B) and at least one output-side component, wherein the at least one input-side (A, B) and at least one output-side component are hardware components which are connected to one another via terminals by means of electric or other lines or signal lines, - in which a respective component fault tree (20A, 20B, 25C, 43A, 43B, 43C, 73A, 73C) is used for the components, - which models a hazard for the component, and - which has at least one input fault mode (21A, 21B, 26C, 44A, 44B, 44C, 45A, 45B, 45C, 74A, 74C, 75A, 75C) or a basic event (22A, 22B, 48A, 48B, 79) and at least one output fault mode (24A, 24B, 46A, 46C, 47A, 47B, 47C, 76A, 76C, 77A, 77C, 78A), wherein the output fault mode and the possibly present input fault mode are each assigned to a terminal (10A, 10B, 41A, 41B, 41C, 42A, 42B, 42C, 71A, 71C, 72A, 72C) of the component, - in which a circuit description is used, which comprises information about the components (A, B, C) of the electric circuit and at least one connection of the components to one another, wherein the circuit description comprises a circuit diagram (40, 70) that can be illustrated graphically, a list of component parts of the circuit together with their properties, a piece of information about the terminals of the component parts and connections of the component parts to one another and/or to the outside, - in which the component fault trees (20A, 20B, 25C, 43A, 43B, 43C, 73A, 73C) of the components (A, B, C) are connected based on the circuit description, wherein an output fault mode of the component fault tree of the input-side component is connected to an input fault mode of the component fault tree of the output-side component if a. the circuit description contains a connection between the assigned terminal of the input-side component (A, B) and the assigned terminal of the output-side component and b. if the output fault mode (24A, 24B, 46A, 47A, 47B, 76A, 77A, 78A) of the component fault tree of the input-side component (A, B) correlates to an input fault mode (26C, 44C, 45C, 74C, 75C) of the component fault tree of the output-side component. - in which the electric circuit has at least one input-side (A, B) and at least one output-side component, wherein the at least one input-side (A, B) and at least one output-side component are hardware components which are connected to one another via terminals by means of electric or other lines or signal lines, - in which a respective component fault tree (20A, 20B, 25C, 43A, 43B, 43C, 73A, 73C) is used for the components, - which models a hazard for the component, and - which has at least one input fault mode (21A, 21B, 26C, 44A, 44B, 44C, 45A, 45B, 45C, 74A, 74C, 75A, 75C) or a basic event (22A, 22B, 48A, 48B, 79) and at least one output fault mode (24A, 24B, 46A, 46C, 47A, 47B, 47C, 76A, 76C, 77A, 77C, 78A), wherein the output fault mode and the possibly present input fault mode are each assigned to a terminal (10A, 10B, 41A, 41B, 41C, 42A, 42B, 42C, 71A, 71C, 72A, 72C) of the component, - which models a hazard for the component, and - which has at least one input fault mode (21A, 21B, 26C, 44A, 44B, 44C, 45A, 45B, 45C, 74A, 74C, 75A, 75C) or a basic event (22A, 22B, 48A, 48B, 79) and at least one output fault mode (24A, 24B, 46A, 46C, 47A, 47B, 47C, 76A, 76C, 77A, 77C, 78A), wherein the output fault mode and the possibly present input fault mode are each assigned to a terminal (10A, 10B, 41A, 41B, 41C, 42A, 42B, 42C, 71A, 71C, 72A, 72C) of the component, - in which a circuit description is used, which comprises information about the components (A, B, C) of the electric circuit and at least one connection of the components to one another, wherein the circuit description comprises a circuit diagram (40, 70) that can be illustrated graphically, a list of component parts of the circuit together with their properties, a piece of information about the terminals of the component parts and connections of the component parts to one another and/or to the outside, - in which the component fault trees (20A, 20B, 25C, 43A, 43B, 43C, 73A, 73C) of the components (A, B, C) are connected based on the circuit description, wherein an output fault mode of the component fault tree of the input-side component is connected to an input fault mode of the component fault tree of the output-side component if a. the circuit description contains a connection between the assigned terminal of the input-side component (A, B) and the assigned terminal of the output-side component and b. if the output fault mode (24A, 24B, 46A, 47A, 47B, 76A, 77A, 78A) of the component fault tree of the input-side component (A, B) correlates to an input fault mode (26C, 44C, 45C, 74C, 75C) of the component fault tree of the output-side component. a. the circuit description contains a connection between the assigned terminal of the input-side component (A, B) and the assigned terminal of the output-side component and b. if the output fault mode (24A, 24B, 46A, 47A, 47B, 76A, 77A, 78A) of the component fault tree of the input-side component (A, B) correlates to an input fault mode (26C, 44C, 45C, 74C, 75C) of the component fault tree of the output-side component.