| 摘要 |
PURPOSE:To protect a coil by providing a voltage/current conversion amplifier circuit, a circuit for monitoring plus and minus operating voltages, and means for short-circuiting the coil or opening the coil current path upon occurrence of abnormal operating voltage. CONSTITUTION:Upon interruption or dropping below a prescribed level of operating voltage due to fault in plus or minus power supply, output current from a voltage/current conversion amplifier circuit 1 increases to a maximum level determined by a current limit resistor R4. At this time, a transistor TR1 is turned OFF to close contacts 6 thus short-circuiting a coil 3. The contacts 6 are inserted in series with the coil 3 so that they are opened upon occurrence of abnormality. |
