LR Lab

1. What is the unit of the quotient of inductance and resistance? Show your work below.

2. The quotient of L and R is called the time constant. The Greek letter tau is used to represent the time constant.
3. An inductor will be fully charged/discharged in a time of 4 to 5 time constants.

1. Open the simulation and select RLC.

2. Construct the circuit to the right.

3. Set values to:
   Battery voltage = 10 volts
   L = 10 henries
   R = 10 ohms

4. Calculate the time constant.

5. Add the necessary meters and sketch the graphs of i vs t, and V vs t, for the resistor and inductor when the inductor is charging and discharging.

NOTE - It is not possible to flip the switches fast enough for LR effects to be observed - try and see.

Here's what has to be done.

RISE of CURRENT

1. Open both switches.

2. Close the top switch.

DECAY of CURRENT

1. Once the inductor has been fully energized, click the PAUSE button.

2. Adjust the switches. Bottom switch to close, Top switch to open.

3. Unpause the simulation.

1. When is the brightness of the bulb increasing?
   
   

2. When is the brightness of the bulb decreasing?
   
   
3. When does the battery supply the potential to light the bulb?
   
   
4. When does the inductor supply the potential to light the bulb?
   
   
5. Does the direction of charge flow change through the inductor? If yes, explain when.
   
   
6. Complete the chart below