What is dielectric substance?

A dielectric substance, often referred to simply as a dielectric, is a material that does not conduct electricity but can support the establishment of an electric field within it. Dielectrics are characterized by their ability to insulate or separate electrical charges. They are used in a wide range of applications, including capacitors, insulators, and as an essential component in various electronic devices and systems.

When a dielectric material is placed between two conductive plates (as in a capacitor), and an electric potential difference (voltage) is applied across the plates, the dielectric reduces the strength of the electric field between them. This property is quantified by the material's relative permittivity (also known as its dielectric constant), which is a measure of how much the electric field within the material is reduced compared to that in a vacuum.

Dielectrics are essential in capacitors because they increase the capacitance of the device. Capacitance is a measure of a capacitor's ability to store electric charge, and it is directly proportional to the surface area of the plates and inversely proportional to the distance between them. By inserting a dielectric between the plates, the distance effectively decreases, increasing the capacitance and the amount of charge the capacitor can store.

Common dielectric materials include plastics, ceramics, rubber, and various insulating materials. The choice of dielectric material depends on the specific requirements of the application, such as the desired capacitance, voltage rating, and operating temperature range.