Capacitor Discharge Time Calculator
Calculate the RC time constant and time to discharge to a target voltage.
Ω
µF
V
V
Time Constant (tau)
1.0000 s
Time to Target Voltage2.4849 s
Time to ~0 V (5 tau)5.0000 s
Time Constant (tau) vs Discharge Resistance
RC Discharge Timing
tau = R x C
V(t) = V_0 x e^(-t/tau)
t = tau x ln(V_0 / V_target)
After 5 time constants, the capacitor is essentially discharged (< 1% of initial).
Example Calculation
100 uF discharging through 10k from 12 V to 1 V.
- 01tau = 10000 x 0.0001 = 1.0 s
- 02t = 1.0 x ln(12/1) = 1.0 x 2.485 = 2.485 s
- 035 tau = 5.0 s to fully discharge
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