If I have a 10 mH inductor with a 1,000 ohm resistor, how long will it take the resistor to reach its maximum value? I have it as 10 millisceonds but my answer was wrong. So is it [5 milliseconds] or [50 microseconds] or [100 microseconds]? I don't know where I screwed up in my calculations? Thank you for the help?
Please convert your 10 mH to 10000H and do your calculation. The time constant is L/R 10 sec. The time constant gives you 63.2 percent of current. See the formula I (E/R)*(1 - ?^-Rt/L). ?^-Rt/L always gives you a positive result whatever the R,t,L is. So (1 - ?^-Rt/L) always less than one. That is why the maximum value of current theoretically never been reach unless t is very long to make ?^-Rt/L minimum.
The time constant is L/R or 10 usec in your case. An exponential circuit will change to with 1% of the final value in 5 time constants, so 5 time constants is often use as the total response time.
