| 摘要 |
PURPOSE:To prevent the occurrence of the influence exerted by the heating of an output resistor and the temperature change of a feedback coil, through a simple constitution, by supplying a given current to the feedback coil working in conformity with a load. CONSTITUTION:A pulse voltage C' with a width, corresponding to a load, is generated in order to perform a digital convertion through the working of an output resistor 10 for detecting the sum of a current flowing to a first feedback coil 5, which generates an electromagnetic power for restoring a balance mechanism 24, and a second feedback coil 6 working in synchronism with the feedback coil 5, and through the working of a differential amplifier 12 and a comparator 14 whereto a saw teeth wave generating output is also added. A current C corresponding to the voltage C' is supplied to a coil 6 through a voltage-current converter 19. By means of a current supplied to the coil 6 for generating an electromagnetic power erasing the electromagnetic power generated by the coil 5, the output of the amplifier 12 is brought to zero, voltages across the resistor 10 become equal to a reference voltage Er, and a flowing current is reduced to a trace amount. This prevents the occurrence of the influence exerted by the heating of the output resistor and the temperature change through a simple constitution, and enables to improve a load measuring precision. |
