Which sensor can use differential pressure to obtain level and flow measurements?

• A. Pressure Sensor
• B. Weather Station
• C. Location Sensor
• D. Rain Sensor

Answer: (A)

Differential pressure sensing is about measuring the pressure difference between two points to infer another quantity. For level, the pressure at the bottom of a liquid column is proportional to its height (rho times g times h). By comparing that bottom pressure to a reference pressure, a differential pressure sensor can calculate the liquid level. For flow, the pressure drop across a restriction (like an orifice or venturi) is related to the flow rate; measuring the delta P across the element lets you determine flow after calibration.

A pressure sensor, especially of the differential-pressure type, is designed to capture that pressure difference and convert it to a level or flow value. The other devices—weather station, location sensor, and rain sensor—do not rely on pressure differences to measure level or flow, so they’re not suitable for this purpose.