如图1,用万用表测量电阻R_x时,表中电流 I=ε/(R_x+(r_g+R+R_0)),由于R_x和I不成正比关系,所以刻度盘上R_x的刻度是不均匀的.虽然万用表刻度上标有从0～∞的电阻值,但由于刻度的不均匀,造成了当指针的偏角太小或太大时,R_x读数的不准确.当R_x=r+g+R+R_0时,I的大小是R_x=0时的一半,这时指针指在刻度盘的中心 As shown in Figure 1, when using a multimeter to measure the resistance R_x, the current I = ε / (R_x + (r_g + R + R_0)) in the table is not uniform because R_x and I are not proportional to each other. Multimeter scale markings from 0 ~ ∞ resistance, but because of the uneven scale, resulting in the pointer deflection is too small or too large, R_x reading inaccurate.When R_x = r + g + R + R_0 When I is half the size of R_x = 0, then the pointer refers to the center of the dial