Electroscope – Accurate device used to detect electrical charges as a kind and consists of two sheets of gold or aluminum capsules at the end of a metal rod ends from the top disk metal passes through the repayment of rubber for saves in a bowl of glass or metal has interface or facets of glass make it easier to see the papers inside.
Electroscope ( from the Greek word “electron” and skopeo – observe , detect ) – a device for detecting electrical charges.
Electroscope consists of a metal rod to which the two strips are suspended paper or aluminum foil. Rod fastened using ebony tube inside a metal housing cylindrical glass lids closed .
Electroscope device based on the phenomenon of electrical repulsion of charged bodies . Charged body in contact , such as grated glass rod , the rod electroscope electric charges are distributed along the rod and leaflets . As like- charged bodies repel each other, then the repulsive force electroscope leaves will move to a certain angle . And the more the amount of charge of the electroscope , the more repulsive force and thus leaves a greater angle they diverge (Figure 1.7 ) . Consequently, the angle differences electroscope leaves can judge the magnitude of the charge located on the electroscope .

If the charged electroscope to bring the body charged opposite sign , for example, is negative, the angle between its leaves begin to decline. Consequently, the electroscope to determine the charge sign of the electrified body .
For the detection and measurement of electric charges also apply electrometer . Its principle of operation is not significantly different from the electroscope . The main part of the electrometer is a lightweight aluminum arrow, which can rotate around a vertical axis . On the corner deflection of the electrometer can judge the magnitude of the charge transferred to the rod of the electrometer .
Calibrate the instrument can determine the electric charge and the potential difference .