Hello All, I have noticed that a similar question have been asked many times here, but I still have doubts how to solve the parallel plates problem defined below: 1. The problem statement, all variables and given/known data We have two freely moving parallel plates of area A, separated by distance d, one is grounded and the other is supplied with voltage from a regulated power supply which can also have its polarity reversed. 1. What is going to happen to the plates at a given voltage V? 2. What will happen to the plates when changing the voltage with constant speed dV/dt? 3. What will happen to the plates at voltage V when the polarity is suddenly changed? 4. How the problem will change when the plates are replaced with grids? 2. Relevant equations See below. 3. The attempt at a solution 1. The plates will attract each other with force F(V,d) = V^2 * e_0 * A / (2 * d^2) 2. As above, but the equation gets more complicated and becomes a function of time. They should meet sooner than in #1. 3. Nothing should happen because of V^2, so sign doesn't play a role. Perhaps I'm underestimating some switching effects here? 4. Again, everything should be the same - to first approximation, ignoring the edge effects and fringe fields near the surface/edges. Could anyone comment on my answers? Thanks.