Capacitor Voltage Equations: Explained

[ace8888]

Homework Statement

Hi, I've run into two different equations for the voltage of a typical RC circuit, one resistor, and one capacitor.
Please explain the different between the two. One has a 1 - the natural log and the other one doesnt.

Homework Equations

1. V(t) = Vo*e^(-t/RC)

2. Vc = Vs(1-e^-t/RC)

The Attempt at a Solution

 

[kuruman]

One of the equations is for a charging capacitor and the other for a discharging capacitor. To figure out which is which, evaluate each expression at t = 0 and at t → ∞ .

 

[ace8888]

One of the equations is for a charging capacitor and the other for a discharging capacitor. To figure out which is which, evaluate each expression at t = 0 and at t → ∞ .

thanks!

 

[haruspex]

One has a 1 - the natural log

It is not a log; it is a negative exponential.
Do you understand what these two curves look like?

 

[ace8888]

It is not a log; it is a negative exponential.
Do you understand what these two curves look like?

Typo, yes it is the natural exponent. I don't know why but i was thinking exponent and typed log. They are inverse of each other.