The Square Root Transmitter ST20 is square root computer. It is designed to solve the equation Q = C √ΔP where ΔP is the differential pressure across an orifice, and C is a constant relating the orifice plate to engineering units. Because ST20 does not use the curve segment, biased diode technique, it provides accuracy and resolution limited only by the stability and calibration of the orifice plate and its transmitter. The ST 20 output is a standard process current or voltage signal that is linearly proportional to flow.