A physical circuit (Figure 1) has been set up in the Lab. Only one student can interact with the hardware at a given time while many can observe it from different places.

After performing this experiment, the student will be able to:

1. Understand the characteristics of a photocell (The relationship between light illumination and resultant resistance)

2. Appreciate the Pulse Width Modulation Concept

3. The working principle of a voltage divider rule.

4. Build a simple alert system to indicate light thresholds limits

1. Open The Experiment User interface

2. Choose Light Controller-tab option (Figure 2)

3. Adjust the LED (In the remote Lab) brightness by Adjusting the PWM slide from 0 to 0.1

4. Wait for a few seconds and record the steady value.

5. Repeat the step 1) and 2) in steps of 0.1 until the dial reaches the value of 1

6. Try to draw a graph of resistance versus time and compare the results with the theory

7. Using the values (Figure 1) and the voltage divider equation, calculate the output voltage for each resistance

8. Using a comparison Vi, and a Boolean indicator create a LabVIEW program to check if the light illumination has exceeded set thresholds.