1. The problem statement, all variables and given/known data An electrode with a varying voltage V = V0 + VACejωt is placed near a plate. The current output from the electrode is then measured. We want to find the relation between the current output and the amplitude of vibration. We can assume VAC is small relative to V0. 2. Relevant equations Idea: 1. Constant charge in plate -> Constant force exerted -> separation changes -> capacitance changes 2. Apply sinusoidal voltage->phase change of force for every ∏ rad -> oscillation 3. these leads to changes in output current detected in electrode. 3. The attempt at a solution V = V0 + VACe(jωt) Q = CV I = V*dC/dt + C*dV/dt I = jCVACωejωt + V*dC/dt C = ε0A/d dC/dt = - (ε0A/d2) * d(d)/dt I = jCVACωejωt + V*(ε0A/d2) * d(d)/dt To find: d(d)/dt F = Q2/(2ε0A) m*dv/dt = Q2/(2ε0A) v = Q2/(2mε0A) * t therefore, the current is: I = jCVACωejωt + Q3/(2ε0Am) * (1/d) * t So the current depends both on time and inversely to displacement?