Abstract: The combined sensor and control comprises a flow sensor through which passes working hydraulic fluid delivered by a pump through a hydraulic power circuit to a hydraulically operated power mechanism which is subjected to variations in load. The sensor senses incipient changes in a preselected rate of flow of the working hydraulic fluid by detection of very slight changes in the differentials in the pressure of the working fluid at opposite sides of a restricting orifice through which the working fluid is constrained to pass. These differentials in pressure, or pressure drops, operate a pneumatic pressure control device by which pneumatic pressure supplied to an actuator through a circuit, isolated from the working hydraulic circuit, is controlled. The pressure control device causes the applied pneumatic pressure to be varied almost instantly in a manner analogous to the slight variations in the normal preselected differential in pressure across the orifice.