An Electroscope is an important laboratory instrument, used for detecting the presence of static electricity. It is used to detect the presence and magnitude of electric charge present in a source. The instrument works on a simple principle and indicates the relative magnitude of charge or voltage of a source.

Gold Leaf Electroscope
The equipment consists of two thin metallic leaves suspended from a metallic hook. When the hook is brought near a source of static electricity, some of the electrons in the hook move onto the leaves (if the source is negatively charged) or pulled up to the hook from the leaves (if the source is positively charged).The similar charged leaves repel each other. The extent to which these leaves open is directly proportional to the charge of the source. Gold, Aluminium and copper foils are popularly used in these electroscopes. This simplest electroscope only indicates the charge and does not measure it.

Capacitance Electroscope
This type of electroscope is generally calibrated, in order to make quantitative measurements. A dielectric material is put between the leaves of the electroscope. This increases the charge in the leaves and allows measurement of the charge or voltage of the source.

Use of Electroscope

• Scientific experiments
• Educational laboratory