The charge and discharge currents flow in opposing directions. The rate at which the capacitor is charged and discharged depends on its capacitance and the value of the series resistor R, and is represented by the time constant T = R•C. On expiry of this time, the capacitor has attained 63% of its final voltage during charging, or lost 63% of its initial voltage during discharging. Once the capacitor is fully charged, no charging current flows any longer; in this state, the capacitor blocks direct current