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Convert the change in capacitance into an electrical signal. The eddy current detection sensor consists of two sets of metal films and electrode plates that form a differential variable capacitor. This capacitor is placed on an electrostatic capacitance detection bridge, with excitation being provided by the oscillation circuit of the RF flow meter. When eddies are generated, the electrostatic capacitance changes, causing the bridge to become unbalanced. This imbalance is amplified through an RF amplification circuit, and after detection, a signal corresponding to the eddy current frequency is obtained. This signal is amplified and shaped into a rectangular wave, which is then output as a current pulse by a constant current circuit. The feedback loop is used to compensate for the imbalance in the bridge caused by temperature changes. https://p3-tt.byteimg.com/origin/pgc-image/efcc8aef42a54fe1865b294abec70e36?from=pc For each velocity distribution profile, the dynamic pressure measurements are taken at 45o intervals, with a step size of 0.25 in along the 7.981 in diameter of the pipe. The pressure sensor used for measurement is a 3-hole “W-probe” manufactured by United Sensor. "The central hole in the configuration of the W-probe can measure the overall dynamic pressure and is used to calculate local flow velocities. Rotate the probe until the pressures at both open ends are balanced; the rotation angle of the probe can then be used to measure the angle of the circumferential flow. Through a motion control system based on stepper motors and a data acquisition system based on a PC, the displacement, rotation, and pressure values of the probe can be measured and controlled. A non-full-pipe electromagnetic flowmeter must measure both the average flow velocity and the liquid level inside the pipe. By connecting the two excitation windings in series in the forward and reverse directions respectively, flow velocity signal potentials measured under two different magnetic field strengths and distributions are generated; the ratio between these two potentials has a certain functional relationship with the liquid level height.