To measure characteristics of a direct current volt meter operating a direct current voltage generator with a computer.

Output of a direct current voltage generator 2 is input in a direct current volt meter 1. A computer 3 controls the direct current voltage generator 2 and a direct current generator 6. A printer 4 and a plotter 5 produces the measured data. The output of the direct current generator 6 is terminated with a load resistance and the both ends are given to the input of the direct current volt meter 1. The direct current generator 6 is built-in the direct current voltage generator 2.