AP Physics C: Electricity and Magnetism / Unit 13: Electromagnetic Induction
13.5 Circuits with Resistors and Inductors (LR Circuits)
Notes
When switched on: $\displaystyle I(t)=\frac{\varepsilon}{R}\left(1-e^{-Rt/L}\right)$, time constant $\displaystyle \tau=\frac{L}{R}$.
- Just after closing, an inductor acts like an open circuit; after a long time, like a wire.
Practice
Right after the switch closes, current through an inductor is:
It resists the sudden change.
After a long time, the current is:
Inductor acts like a wire.
$L=0.5$ H, $R=10$ Ω. $\tau=$
$\displaystyle \frac{L}{R}$.
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