When in the external feedback mode, the electrometer will display the voltage across the feedback element. The unknown charge can be calculated from the following formula.
在外部反馈模式下，静电计显示反馈元件上的电压。未知电荷可以由下式计算。
2
So far both the formula for energy of line charge and the condition of electrostatic equilibrium have not been directly derived from the current electromagnetism.
现行的电磁学对线电荷的能量公式、静电平衡条件都没有直接推导过。
3
The article infers two spinor formula of charge. It shows the essence of charge.