答案:量程为0~75mV,0.2级毫伏表的允许误差 Δ1=75×0.2%=0.15mV
量程为0~300mV,0.1级毫伏表的允许误差 Δ2=300×0.1%=0.3mV
而根据题意测量60mV电压的误差要求不大于 Δ=60×0.4%=0.24mV 应选用75mV,0.2级毫伏表。
答案:量程为0~75mV,0.2级毫伏表的允许误差 Δ1=75×0.2%=0.15mV
量程为0~300mV,0.1级毫伏表的允许误差 Δ2=300×0.1%=0.3mV
而根据题意测量60mV电压的误差要求不大于 Δ=60×0.4%=0.24mV 应选用75mV,0.2级毫伏表。