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Please help A2 physics question about calculating time constant? Watch

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    I have a exponential growth curve for a potential difference vs time graph. Is it possible to calculate the time constant from the gradient of the curve at time 0 seconds?
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    (Original post by Jas1947)
    I have a exponential growth curve for a potential difference vs time graph. Is it possible to calculate the time constant from the gradient of the curve at time 0 seconds?
    The easiest way to measure the time constant from an exponential graph where the capacitor is charging would be to first calculate  (1- \frac{1}{e}) \times Max P.D , then use the graph to see which time corresponds to this value of P.D

    If it were discharging you would use a similar method but using 1/e instead
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    (Original post by Jas1947)
    I have a exponential growth curve for a potential difference vs time graph. Is it possible to calculate the time constant from the gradient of the curve at time 0 seconds?
    Yup. Just draw a tangent to the curve at t=0; also draw a line representing the asymptote of the steady-state value. The crossing point of the two on the x-axis represents the time constant.

 
 
 
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