A position sensor is provided, particularly a sensor applicable to a linear compressor, for detecting the position of the piston and preventing the latter from knocking against the head located at the end of its stroke. More particularly, there is provided a sensor, particularly one that is employable in detecting the position of a piston of a compressor, the piston being axially displaceable inside a hollowed body, the compressor comprising a valve blade, the blade being positioned between the head and the hollowed body, the sensor comprising a probe electrically connected to a control circuit, the probe being capable of detecting the passage of the piston by a point of the hollowed body and signaling this to the control circuit. An associated compressor employing such a sensor is also provided.