Answer 2
The storage capacitance is given by the equation C = Q / V, where Q = charge and V = voltage. But Q = I × t, where I = current and t = time for which the current flows. Therefore, C = I × t / V. Given that the discharge current I = 0.1 pA, the refresh time t = 20 ms and the voltage drop V = 0.5V, the capacitance of the cell is:
C = 0.1 pA × 20 ms / 0.5 V = 4 × 10–15 F

Contributor: Naveen PN

Published: July-2002