Drift Velocity

The drift velocity is the average velocity that a particle, such as an electron, attains due to an electric field. It can also be referred to as axial drift velocity since particles defined are assumed to be moving along a plane. In general, an electron will 'rattle around' in a conductor at the Fermi velocity randomly. An applied electric field will give this random motion a small net velocity in one direction.

In a semiconductor, the two main carrier scattering mechanisms are ionized impurity scattering and lattice scattering.

Because current is proportional to drift velocity, which is, in turn, proportional to the magnitude of an external electric field, Ohm's law can be explained in terms of drift velocity.

Drift velocity is expressed in the following equations:, where is the current density, is charge density in units C/m3, and vavg is the average velocity of the carriers (drift velocity);

  • , where μ is the electron mobility in (m^2)/) and E is the electric field in V/m.

Read more about Drift Velocity:  Numerical Example

Other articles related to "drift velocity, velocity, drift":

Electron Mobility - Electric Field Dependence and Velocity Saturation
... At low fields, the drift velocity vd is proportional to the electric field E, so mobility μ is constant ... As the electric field is increased, however, the carrier velocity increases sub-linearly and asymptotically towards a maximum possible value, called ... This velocity is a characteristic of the material and a strong function of doping or impurity levels and temperature ...
Cyclonic Separation - Alternative Steady State Analysis
... The particle and the fluid are moving along a curved trajectory with tangential velocity with a radius of curvature of ... drag between the particle and the fluid parallel to the velocity, there are two other forces acting on the particle - radial viscous drag and buoyancy ... the fluid is given by where is the radial drift velocity of the particle through the fluid and the sign reflects the opposition of the force to the ...
Drift Velocity - Numerical Example
... The drift velocity therefore can be calculated By comparison, the Fermi velocity of these electrons (which, at room temperature, can be thought of as their approximate velocity in the ... case of alternating current, the direction of electron drift switches with the frequency of the current ... In the example above, if the current were to alternate with the frequency of F=60 Hz, drift velocity would likewise vary in a sine-wave pattern, and electrons would fluctuate about their initial ...
Electron Mobility - Introduction - Drift Velocity in An Electric Field
... faster and faster instead it moves with a finite average velocity, called the drift velocity ... electrons and holes, will typically have different drift velocities for the same electric field ... In these cases, drift velocity and mobility are not meaningful ...
Classical And Quantum Conductivity - Conductivity - Classical Conductivity
... The average velocity due to the thermal energy is zero since the electrons are going in every direction, leading to velocity vectors that are randomly oriented ... The electrons are given a velocity away from the (negative source of the) field, which leads to these collisions with the fixed ions ... a release of it), is a small value called drift velocity ...

Famous quotes containing the word drift:

    But now they drift on the still water,
    Mysterious, beautiful;
    William Butler Yeats (1865–1939)