what is the mathematical expression for the voltage across a charging capacitor?
Best Answer: 1. voltage on a cap, charging v = vâ[1âe^(ât/Ï)] vâ is the final voltage 2. voltage on a cap, discharging v = vâe^(ât/Ï) vâ is the initial voltage on the cap R is resistance in ohms, C is capacitance in farads t is time in seconds RC = Ï = time constant v = vâe^(ât/Ï) v/vâ = e^(âÏ/Ï) = 1/e = 0.368.