| 摘要 |
PURPOSE:To enable to perform a precise conversion of a power without being influenced by a voltage, a frequency, and a wave-form of a signal to be converted, by a method wherein, after an input signal is converted in a logarithmic manner, it is added, and the addition signal is converted in an inverse logarithmic manner. CONSTITUTION:A voltage between lines to be measured is applied to an input terminal 2 for voltage of a multiplication circuit Q1 via a potential transformer PT and resistance type potential dividers R1, R2, and a load current is applied to an input terminal 3 for current via a current transformer CT. The current, converted in a logarithmic manner by means of logarithmic circuits 4 and 5, reaches an addition circuit 6, and a signal further added is converted in an inverse logarithmic manner by means of an inverse logarithmic conversion circuit 7 to reach a multiplication output terminal 8. The multiplied output is then outputted as a power conversion signal via a smoothing circuit 11 and a current amplification circuit 12. This improves straightness and permits the reliable conversion of even a wide range of a voltage. |
