Transient response of RL circuit

A voltage step is applied to a series RL circuit and the resulting voltage variation across the capacitor is captured and analyzed. 

Wiring Diagram   Photograph of the experimental setup.
The voltage steps are generated on OD1 by clicking on the buttons on the GUI. The observed waveforms are shown below, showing the voltage variation across the inductor in each case. It can be observed that when a 5 to 0 volt step is applied, the polarity of the voltage across the inductor is reversed and the voltage goes to negative immediately. After that the voltage reduces exponentially, driving a current through the resistor. The resulting wave form is fitted with V = Vo x exp(R/L * t) to extract the R/L value. The value of inductor is calculated from  that.

Screen shot of the voltage across an inductor.