A device that uses a temperature coefficient pre-calibrated for the device for measuring a flow within the device, the device comprising: a flow path ; a flow restriction portion disposed in the flow path that creates a differential pressure within the flow path; a differential pressure sensor configured to generate a differential pressure signal based upon the differential pressure within the flow path; a temperature sensor configured to sense a temperature at or near the differential pressure sensor; a processor that receives signals from the differential pressure sensor including the amplified signals from the differential amplifier, the processor calculating a flow rate based on the signals from the differential pressure sensor, the amplified signals being corrected based upon a predetermined temperature coefficient, characterized in that the device further comprises a differential amplifier that amplifies differential pressure signals from the differential pressure sensor ; and an A-D converter that converts amplified signals into digital signals for processing by the processor ; wherein the differential pressure sensor is periodically auto-nulled; wherein the processor includes a pulse width modulator adapted to modulate signals to obtain pulse width modulated signals for transmission through the differential amplifier , wherein a duty cycle of the pulse width modulated signals varies based on the pre-calibrated temperature coefficient and an output from the differential pressure sensor and the temperature sensor; wherein the processor is adapted to adjust the duty cycle of the pulse width modulated signals transmitted from the processor such that high gain signals are essentially at mid-scale on the A-D converter . a flow path ; a flow restriction portion disposed in the flow path that creates a differential pressure within the flow path; a differential pressure sensor configured to generate a differential pressure signal based upon the differential pressure within the flow path; a temperature sensor configured to sense a temperature at or near the differential pressure sensor; a processor that receives signals from the differential pressure sensor including the amplified signals from the differential amplifier, the processor calculating a flow rate based on the signals from the differential pressure sensor, the amplified signals being corrected based upon a predetermined temperature coefficient, characterized in that the device further comprises a differential amplifier that amplifies differential pressure signals from the differential pressure sensor ; and an A-D converter that converts amplified signals into digital signals for processing by the processor ; wherein the differential pressure sensor is periodically auto-nulled; wherein the processor includes a pulse width modulator adapted to modulate signals to obtain pulse width modulated signals for transmission through the differential amplifier , wherein a duty cycle of the pulse width modulated signals varies based on the pre-calibrated temperature coefficient and an output from the differential pressure sensor and the temperature sensor; wherein the processor is adapted to adjust the duty cycle of the pulse width modulated signals transmitted from the processor such that high gain signals are essentially at mid-scale on the A-D converter . <EOS>