# Displacement Current Drivel

Riposte
I make the commitment that anyone wishing to counter any assertion made on this site will be guaranteed a hyperlink to a website of their choosing at the point where the disputed assertion is made.    ivor@ivorcatt.com

Ivor Catt. 18june02

Displacement Current Drivel

Clearly this guy lacks confidence. “There is some discussion whether the actual pickup is due to displacement current or simply some sort of general electromagnetic pickup, that is obviously filling the area.” More honest than most. Give him B minus. - Ivor Catt, 23may02

“Taking this as a hint, Maxwell made the hypothesis that the vacuum was not really empty at all, but was instead filled with atoms of a very fine and insensible material which he called the   ether. When electric energy was stored in space, Maxwell took this to mean that the atoms of the ether became stretched, just like the atoms in paper or oil.”

I have Maxwell’s Treatise. What page please? Ivor Catt 23may02

Now for some pure drivel;

# Time-dependent simulation

The time-dependent form of the drift-diffusion equations can be used both for steady-state and transient calculations. Steady-state analysis is accomplished by starting from an initial guess, and letting the numerical system evolve until a stationary solution is reached, within set tolerance limits. This approach is seldom used in practice, since now robust steady-state simulators are widely available. It is nonetheless an appealing technique for beginners since a relatively small effort is necessary for simple applications and elementary discretization approaches. If an explicit scheme is selected, no matrix solutions are necessary, but it is normally the case that stability is possible only for extremely small timesteps.

The simulation of transients requires the knowledge of a physically meaningful initial condition, which can be obtained from a steady-state calculation. The same time-dependent numerical approaches used for steady-state simulation are suitable, but there must be more care for the boundary conditions, because of the presence of displacement current during transients. In a transient simulation to determine the steady-state, the displacement current can be neglected because it goes to zero when a stationary condition is reached. Therefore, it is sufficient to impose on the contacts the appropriate potential values provided by the bias network. In a true transient regime, however, the presence of displacement currents manifests itself as a potential variation at the contacts, superimposed to the bias, which depends on the external circuit in communication with the contacts. Neglect of the displacement current in a transient is equivalent to the application of bias voltages using ideal voltage generators, with zero internal impedance. In such a situation, the potential variations due to displacement current drop across a short circuit, and are therefore cancelled. In this arrangement, one will observe the shortest possible switching time attainable with the structure considered, but in practice an external load and parasitics will be present, and the switching times will be normally longer. A simulation neglecting displacement current effects may be useful to assess the ultimate speed limits of a device structure.

Some very pretty looking pure drivel is at: