| 摘要 |
<p>PURPOSE:To miniaturize a current transformer while detecting even alternating current containing a current inversion and DC components at a high accuracy and with ease by accurately detecting bipolar primary current to be measured with a slit-free continuous output waveform. CONSTITUTION:A unit A is a logic circuit for outputting an operation command of a changeover switch SW1, Vo+ is a voltage across a load resistance RL1 and Vo is a voltage across the load resistance RL1 or RL2 after passing through the changeover switch SW1 whose output becomes Vo=Vo+ when the changeover switch SW1 is ON and Vo=-Vo- when the changeover switch SW1 is OFF. At the time t5 and t8, the polarity is determined on individual output voltages Vo+ and Vo- for each cycle to control the turning ON and OFF of the changeover switch SW1. Therefore, when the primary current I is I>0, the output voltage Vo is Vo>0 while the absolute value thereof is proportional to primary current I. When I<0, Vo<0 while the absolute value thereof is proportional to the primary current I.</p> |
