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维修英国SP—500型分光光度计(Unicam公司),一般来讲,是将仪器灵敏度控制旋钮调在最大。在仪器暗电流光闸关闭的情况下,可按图示所注各点工作电压进行测量,以确定故障部位。例如当图中B_3(干电池)电压过高,或电流放大管(V_2)衰老或损坏后,会出现T_3点工作电压不对,暗电流控制旋钮,不能使微安表的指针从极左位置移向中间位置。断开
Repairing a British SP-500 spectrophotometer (Unicam) is, in general, adjusting the instrument sensitivity control knob to its maximum. When the dark current shutter of the instrument is turned off, the working voltage at each point in the figure can be measured to determine the fault location. For example, when the B_3 (dry cell) voltage in the figure is too high, or the current amplification tube (V_2) is aging or damaged, the operating voltage at the T_3 point is incorrect. The dark current control knob cannot move the microammeter pointer from the extreme left position. centre position. disconnect