The core of the electromagnetic converter uses a high-speed CPU. The calculation speed is fast, the precision is high, and the measurement performance is reliable. The input impedance is up to 1015 ohms, the common-mode rejection ratio is better than 100db, the anti-interference ability of 60Hz/50Hz is better than 90db, and the flow rate of the fluid medium with low conductivity can be measured. The sensor adopts non-uniform magnetic field technology and special magnetic circuit structure, the magnetic field is stable and reliable, greatly reduces the volume, reduces the repetition, and has the characteristics of small flow quantization.