# Calculate Displacement Current from Electric Flux Density

• JustStudying
In summary, the conversation discusses the calculation of displacement current density when given the electric flux density vector (xy, yz, xz). If the differentiation of electric flux density results in 0, it means that the field is electrostatic and not time varying. This can be seen in an example of a D.C voltage across a capacitor, where the current eventually becomes 0 due to the constant voltage. Therefore, in the absence of a time varying electric flux density, there will be no displacement current.

## Homework Statement

If electric flux density (D) is given by the vector (xy,yz,xz) then calculate the displacement current density

Jd = dD/dt

## The Attempt at a Solution

if you differentiate D, in terms of t, then you just get 0..but that apparently isn't the answer

If you are getting a "0" as differentiation of electric flux density that means that electric flux density is not changing with time,which means it is electrostatic and not time varying field. You can see this from an example, by keeping D.C voltage across capacitor the current in circuit becomes zero eventually this is because voltage is constant or of zero frequency. So if you don't have a time varying electric flux density there won't be displacement current.