基于I-F变换的弱电流测量仪的研制

Development of a Kind of Weak Current Tester Based on I-F Conversion

在射线测量中常常需要对变化很慢又很弱的电流信号（10^-7～10^-15A甚至更小）进行测量，而用普通的电流表是无法测量这样小的电流的．介绍一种基于I-F变换的弱电流测量仪的工作原理和电路设计．该测量仪是先将电流信号转换成锯齿波的电压信号，再将其转变成频率信号，通过测量频率来间接地测量电流，因此，具有稳定性好和抗干扰能力强的优点．

The current signals which change very slowly and are rather weak （to the extent of 10^-7 -10^-15 A, or even smaller） are usually required to be measured in measuring rays. However, the signals are so small that they can not be measured by regular current meters. This paper introduced the working principles and circuit design of a weak current meter based on I-F transition. The weak current meter first changes the current signals into the voltage signals which present in saw tooth waves, then into the frequency signals. Thus the current can be indirectly measured by measuring frequency. Hence, the weak current meter possesses the advantages of good stability and strong resistance to interference.