Voltage Divider for LED Brightness Control

Objective

To understand how a voltage divider circuit can be used to control the brightness of an LED by adjusting the voltage applied to it.

Materials

• 1 x LED
• 2 x Resistors (e.g., 1kΩ and 10kΩ)
• Breadboard
• Jumper wires
• DC power source (e.g., 9V battery or power supply)
• Multimeter (optional, for measuring voltage)

Circuit Diagram

Connect the circuit as shown in the diagram below. The voltage divider consists of two resistors in series, with the LED connected across the second resistor.

Theory

A voltage divider circuit splits the input voltage between two resistors. The output voltage is taken from the connection between the two resistors and is calculated using the formula:

V_out = V_in * (R2 / (R1 + R2))

By selecting different resistor values, we can adjust the output voltage to control the LED brightness.

Procedure

1. Place the two resistors (R1 and R2) in series on the breadboard.
2. Connect the positive terminal of the power supply to one end of R1.
3. Connect the junction between R1 and R2 to the anode (positive leg) of the LED.
4. Connect the cathode (negative leg) of the LED to the ground terminal of the power supply.
5. Connect the other end of R2 to the ground terminal of the power supply.
6. Power the circuit and observe the LED brightness. Measure the output voltage with a multimeter if available.

Observations

Record the brightness of the LED at different resistor values. Adjust the resistor values to see how the output voltage affects LED brightness.

Conclusion

This experiment demonstrates that a voltage divider can be used to control the brightness of an LED by adjusting the voltage applied to it. By changing resistor values, we can vary the output voltage, which in turn affects the LED brightness.