okay my Question is on discharging capacitors.

the equation for instantanious voltage of a capacitor whilst dischargeing is : v=Vi*e^-t/R*C

However im not sure how to find the

__for a capacitor to completely discharge to zero volts.__

*time*When I transpose for t

t=-(R*C)*ln(v/Vi)

and input v as zero (cap has completly discharge) we get an undefined answear.

I havnt studied calculus and am not familiar with the concept of limits.

how would I go about finding the precise time for a capacitor to discharge without using a normalised universal time constant curve to estimate the answear.

thanks in advance