In order to solve these problems,the F/V conversion circuit is designed.

Design of a kind of V/F converter circuit for high voltage measuring system;

This paper introduces the basic principles of an electronic current transformer, designs a kind of V/F converter circuit that has good practicability in super-current measurement system shown by the experimental results.

Design of V/F conversion circuit of electronic weighing sensor;

The advantages of V/F conversion circuit was also presented.

Then with V/F conversion instead of A/D conversion and using chip microcomputer,long-distance transmission is achieved after boosting the changing frequency signal by transformer.

The system includes the operational amplifier, filter circuit, rectifier circuit, voltage-frequency converter, central control unit and the show circuit etc.