Which sensor would NOT be used to determine when a cylinder has reached the end of its stroke?

A tachometer is primarily used to measure the rotational speed of a shaft or the engine speed in a machine. It provides information about how fast a rotating component is moving but does not directly indicate whether a hydraulic cylinder has reached the end of its stroke. In contrast, sensors like contact limit switches or non-contact limit switches are specifically designed to detect the position of the cylinder, signaling when it has fully extended or retracted. A pressure switch, while more commonly associated with monitoring system pressure, can also be wired to signal when a cylinder has reached its stroke by interpreting the pressure change at the end of the stroke. Thus, the tachometer's function does not align with the specific requirement of determining the position of a hydraulic cylinder in this context.