# physics

posted by Jason

With V = Voe^-(t/T), how many time constants does it take for a capacitor to discharge less than 1% of its initial voltage?

1. Elena

U =U₀exp(-t/T)
U/U₀ =exp(-t/T)
ln(U/U₀) = -t/T
ln(0.01U₀/U₀) =ln0.01 = -t/T
t=-Tln0.01=4.61 T

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