Electrometer

An electrometer comprising:

• a sensing module comprising an electrostatic sensing element, a first electrode, a second electrode, a third electrode, and a fourth electrode;
• wherein the first electrode and the fourth electrode are located on the two opposite ends of the electrostatic sensing element, and the second electrode and the third electrode are located on a middle part of the electrostatic sensing element;
• a control module coupled to the electrostatic sensing element via the first electrode, the second electrode, the third electrode, and the fourth electrode;
• wherein the electrostatic sensing element is single walled carbon nanotube or few-walled carbon nanotube, the control module is configured to measure a resistance variation ΔR of the electrostatic sensing element and convert the resistance variation ΔR into a static electricity potential.