Nanovoltmeters and nanovolt preamplifiers will rarely indicate zero when no voltage is applied to the input, since there are unavoidable voltage offsets present in the input of the instrument.

• 当输入端没有施加电压时，纳伏表和纳伏前置放大器很少会指示零读数。这是因为在仪器的输入端不可避免地存在着电压偏置。