Afghan Farmers: Opium Is The Only Way To Make A Living. Afghan Farmers: Opium Is The Only Way To Make A Living. An Afghan farmer collects raw opium as he works in a poppy field in Nangarhar province on April 29. Poppy cultivation reached a record high this year despite Western efforts to reduce it. An Afghan farmer collects raw opium as he works in a poppy field in Nangarhar province on April 29.
Best Answer: 1. voltage on a cap, charging v = vâ[1âe^(ât/Ï)] vâ is the final voltage 2. voltage on a cap, discharging v = vâe^(ât/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 = vâe^(ât/Ï) v/vâ = e^(âÏ/Ï) = 1/e = 0.368.
The voltage on a discharging capacitor, with time constant T, and initial voltage Vo, varies with time exponentially as; V(t) = Voe^-t/T. So the voltage after one time constant is; V(T) = Vo/e (about 46% of Vo) The Charging eq is; V(t) = Vo[1 - e^-t/T] The voltage after one time constant is; V(T) = Vo[1-1/e] (about 54% of Vo) Since e=2.718 it is common practice to approximate this as ~ 3. Then the discharge voltage afer one time constant is approximately (1/3)Vo And the charging voltage after one time constant is approximately (2/3)Vo