Practicing Success
a b c d |
b |
$ V_C = 200(1 - e^\frac{-t}{\tau}) = 120$ $\Rightarrow e^\frac{-t}{\tau} = 0.4 $ $\Rightarrow \frac{t}{\tau} = ln 2.5 = 0.92$ $ \tau = \frac{5}{0.92} = RC$ $\Rightarrow R = \frac{5}{0.92\times 2 \times 10^{-6}} = 2.7 \times 10^6 \Omega$ |