| 摘要 |
PURPOSE:To reduce the leak current flowing from an endoscope to an operator and an examinee as low as possible by automatically changing over the impedance inserted between a P-electrode and the endoscope in response to a change of a monitor state by an impedance change-over means. CONSTITUTION:The terminal voltage of a cautery power supply detected by a voltage detection circuit 13 is converted to a detection signal shown as an absolute value by an absolute value circuit 15 to be sent to one of the input terminals of a divider circuit 17. The scope earth potential detected by a voltage detection circuit 14 is converted to a detection signal shown as an absolute value by an absolute value circuit 16 to be sent to the other input terminal of the divider circuit 17. By this method, the mutual division of the outputs of the absolute value circuits 15, 16 is performed in the divider circuit 17 and the division output is sent to a control circuit 18 which in turn controls the driving of a change-over circuit 12 and that of alarms 19, 20. That is, on the basis of the division result of the divider circuit 17, an impedance inserting condition reducing a scope leak current, pref. bringing said current to zero is set. |
