With this shield in place, the noise current generated by the electrostatic voltage source and the coupling capacitance flows through the shield to ground rather than through the signal conductors.
有了这种屏蔽，由静电电压源和耦合电容产生的噪声电流就经过屏蔽流到地，而不再流过信号线。
2
Connect the shield of the test fixture to the LO of the electrometer and connect the LO of the electrometer to the LO of the source.
将测试夹具的屏蔽端连到静电计的LO端，再将静电计的LO 端连到源的LO端。
3
Shield current source is controlled by using variable power circuit, this greatly improves dynamic range.