Self-powered, matched wheatstone bridge flow sensor

A Wheatstone bridge flowmeter is provided with a flow channel on a top surface of the base substrate, with two resistors of the Wheatstone bridge in thermal communication with the flow channel. One resistor in the flow channel, on one side of the Wheatstone bridge, has a negative coefficient of resistance (NTC) and the other resistor in the flow channel, on the other side of the Wheatstone bridge, has a positive coefficient of resistance (PTC). At least two of the resistors in the Wheatstone bridge are mounted in at least one cavity space, so that one resistor on each side of the Wheatstone bridge is in thermal isolation from the flow channel, thereby allowing sensing of voltages across the Wheatstone bridge according to fluid flow through the flow channel.