Abstract: A system for measuring the velocity of a fluid can comprise a temperature sensor, for measuring the ambient temperature of the fluid, an RTD placed in the flow path of a fluid, the RTD being included as part of a Wheatstone bridge circuit, a digital potentiometer, the digital potentiometer also being included as part of a Wheatstone bridge circuit, and a controller coupled to the temperature sensor, the RTD and the digital potentiometer. In the system, the controller adjusts the digital potentiometer in response to an ambient fluid temperature signal from the temperature sensor such that the temperature of the RTD remains at a constant differential temperature above the ambient fluid temperature.