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Question 19.12: If a RC circuit has a time constant of 1 s, how long will it......

If a RC circuit has a time constant of 1 s, how long will it take for v_{R} to drop from 100 to 50 V?

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Write the time equation for voltage decay, Eq. (19-24).

t=R C \ln \frac{V}{v} ~~~~ \text{(19-24)} \\ =1\left(\ln \frac{100}{50}\right)=\ln 2=0.693\ s

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