| 摘要 |
PROBLEM TO BE SOLVED: To provide a reactive power computing device and a reactive energy measuring device reducing the number of analogue parts and the size in spite of formation of LSI for lowering costs. SOLUTION: A voltage V1 and a current A1 inputted from input terminals T1, T2 are A/D converted by delta modulators 101, 102 individually so as to be turned into 1-bit output data. The 1-bit output data of the delta modulator 101 is delayed by a 90 deg. equivalent of the input voltage V1 by means of a phase shifting circuit 115 using an RAM (semiconductor memory) or a shift register, and then, reactive power is computed by a circuit in the subsequent stage. In this constitution, the number of analogue parts can be lowered, while the size of the device can be reduced even if formation into an LSI is carried out, so that the costs can be lowered. |
