1. The problem statement, all variables and given/known data A circuit with a battery that is in parallel with a resistor R1 followed series by a capacitor, which is in parallel with a resistor R2 2. Relevant equations Time constant = RC 3. The attempt at a solution I do not know if it is correct to calculate RC with 1/Req = 1/R1 + 1/R2 or if I would only use R1 because it is in series with the capacitor. Can anyone explain?