Practical problems concerning direct current measurement in very shallow water including the dynamic equation and performance of a rotor type current meter are discussed in this paper.

This paper introduce in detail the principle of the calibration of resistance box by method of direct current digital voltage meter, mathematics model and the way of uncertainty evaluation.

This Article Mainly Introduced the Performance, Speciality and Function of CS7106GP, and the Application of the IC in the Digital Direct Current Voltage Meter.