True or False: Schematic diagrams must show contacts de-energized.

Schematic diagrams are a crucial tool in understanding electrical systems and devices. The statement that they must show contacts de-energized is true because schematic diagrams typically represent the circuit as it would appear in its normal (de-energized) state. This provides a clear and consistent way to depict the components and their relationships without the complexities introduced by live conditions.

By showing the contacts in a de-energized state, schematic diagrams allow technicians and engineers to easily interpret the functionality and interactions of various elements within the circuit, making troubleshooting and design processes more intuitive. This method ensures that the viewer does not have to account for the conditions of operation, which can vary widely, and instead focuses on the inherent layout and intended operation of the system when it is not energized.

In contrast, other options that suggest circumstances or conditions under which a diagram may be drawn differently do not align with the standard practice for schematic representations. This reinforced emphasis on de-energized states ensures clarity and uniformity across schematics in electrical engineering.