Electricity & Megnetism

# Flat Capacitor

Capacitors or capacitors are devices responsible for storing electrical charges. They are represented by armor, whose symbol is:

The flat capacitor is a device made by two metal plates. These plates must necessarily be equal and flat, have the same size and be close to each other. Between them is placed the dielectric, an insulator.

The calculation of the flat capacitor is represented by the equation:

Where:
C = capacitance of the flat capacitor
ɛ = permittivity of the medium
A = area of ​​the plates
d = distance

The permittivity of the medium has the same value as the permittivity of the vacuum, that is:

ɛ = ɛ 0 K
ɛ 0 = 8.8 . 10-12 F/m

The relationship between the permittivity constants of the medium and the vacuum is given by the expression:

When there is a need to increase the capacitance of the flat capacitor, it is essential to:

• Increase the area of ​​the plates (arms) • Bring the plates (arms)
closer together
• Place a dielectric with a higher dielectric constant between the plates

When the flat capacitor is connected to an electric generator, this capacitor becomes electrified in order to establish an electric field, whose mathematical representation is given by the equation:

In this case, the potential difference between the armatures is represented by the letter U.
E = Electric field
d = distance