RL-Circuits

Provided the resistivity of an 18 gauge copper wire, the number of turns in an coil consisting of the 18 guage wire, and the length of one side of the coil, we are able to find the resistance of the wire. Then dividing our calculated inductance by this resistance, we were able to find the time constant of this circuit, theoretically

With the switch open, we can find the time constant just by treating the circuit as if all that were present were the inductor and the 120 ohm resistor. 

In the top right corner, we find the time constant for this circuit given the values of the inductor and the resistance. Then we find the the current at 170 microseconds, which turns out to be 0.16 amps. Then we used kirchhoffs laws to find the voltage drop across various circuit elements. As you can see, as time goes to infinity the current reaches EMF/R, but it never quite reaches it because e^-(tR/L) never reaches zero. The current reaches its maximum level asymptotically. The amount of energy in the inductor is represented by one half the product of the inductor and the square of the current.