Displacement Current Calculator:
Enter the values of displacement current dendity, Jd(A/mm2) and area of the capacitor, S(mm2) to determine the value of Displacement current, Id(A).
Displacement Current Formula:
Displacement current is a quantity appearing in Maxwell’s equations that accounts for the rate of change of the electric field in a capacitor or dielectric material, which can produce a magnetic field similar to a conduction current.
It is particularly significant in situations where electric fields change rapidly, such as in alternating current (AC) circuits and electromagnetic waves.
Displacement current allows for the continuity of current in circuits without actual charge flow, ensuring the validity of Ampère’s law.
Cross-sectional area, S is the area through which the displacement current is considered to flow, such as the area between the plates of a capacitor.
When an electric field in a dielectric changes over time, such as when a capacitor is charging or discharging, it creates a displacement current. This change in the electric field induces a magnetic field, similar to the way a conduction current does.
In a capacitor, as an alternating current (AC) voltage is applied, the electric field between the plates changes. Although no actual charge carriers move through the dielectric, the changing electric field generates a displacement current.
This displacement current ensures the continuity of current in the circuit and maintains the magnetic field in the region between the capacitor plates.
Displacement current, Id(A) in amperes is calculated by dividing the displacement current dendity, Jd(A/mm2) in amperes per millimetre square by area of the capacitor, S(mm2) in millimetre square.
Displacement current, Id(A) = Jd(A/mm2) / S(mm2)
Id(A) = displacement current in amperes, A.
Jd(A/mm2) = displacement current density in amperes per millimetre square, A/mm2.
S(mm2) = area of the capacitor in millimetre square, mm2.
Displacement Current Calculation:
- Calculate the displacement current for a displacement current density of 5 * 10-6 A/m2 and a surface area of 0.01 m2.
Given: Jd(A/mm2) = 5 * 10-6, S(mm2) = 0.01 m2.
Displacement current, Id(A) = Jd(A/mm2) / S(mm2)
Id(A) = 5 * 10-6 / 0.01
Id(A) = 5 * 10-8A.
- Suppose a displacement current of 2 microamperes flows through a capacitor with a surface area of 0.05 m2. Calculate the displacement current density.
Given: Id(A) = 2 * 10-6A, S(mm2) = 0.05 m2.
Displacement current, Id(A) = Jd(A/mm2) / S(mm2)
Jd(A/mm2) = Id(A) * S(mm2)
Jd(A/mm2) = 2 * 10-6 * 0.05
Jd(A/mm2) = 4 * 10-5A/mm2.