Operating circuit for hot-wire air flow sensor and sensor applying operating circuit

The invention discloses a working circuit for a hot wire type air flow sensor and a sensor operating circuit. The working circuit comprises a constant temperature control circuit for a hot wire resistor RS and an output signal adjusting circuit; the hot wire resistor RS and a precision resistor R2 are connected in series to form a hot wire arm of a Wheatstone bridge; a temperature compensation resistor RC and a precision resistor R3 are connected in series to form a cold wire arm of the Wheatstone bridge; the negative electrode of the Wheatstone bridge is grounded through a resistor R1, and the positive electrode of the Wheatstone bridge is connected to the output end of a first operational amplifier; the non-inverting input end of the first operational amplifier is connected with reference voltage Uref through a resistor R5, and the reverse input end of the first operational amplifier is connected to the output end of a fourth operational amplifier; the output end of the fourth operational amplifier is selec