Which of the following is NOT a basic component of a mechanical assembly?

In the context of mechanical assemblies, the basic components typically include elements that directly contribute to the mechanical function of the assembly itself. Fasteners, bearings, and gears are fundamental as they play critical roles in connecting parts, supporting rotational situations, and facilitating movement, respectively.

Bearings reduce friction between moving parts and support loads, ensuring smooth operation. Gears transmit motion and torque between components, effectively changing speed and direction. Fasteners, such as screws and bolts, are essential for holding components together securely, providing structural integrity to the assembly.

While sensors can be essential for certain applications, especially in automated systems or in monitoring functionalities, they are not considered a core mechanical component. Instead, sensors serve as additional devices that enhance or monitor the operation of a mechanical assembly but do not serve a direct mechanical function like the other components listed. Thus, this distinction is what makes sensors different from the basic mechanical components like bearings, fasteners, and gears.