A fluid flow rate responsive signal generator includes moveable members which, in part, define a pair of paths for the flow of fluid. A first of the moveable members is a shuttle which supports a magnetic field generator, the shuttle being displaced toward a proximity switch in response to fluid flow. The second moveable member functions as a valve which, when in the open condition, allows flow to bypass the flow path in which the shuttle is disposed. The bypass flow path control valve member will be automatically positioned as a function of the dynamic flow conditions and may be either normally closed or prepositioned to define a minimum bypass flow path area.

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