Capacitive Voltage Divider Experiment

Objective of Capacitive Voltage Divider Experiment

In this experiment, you will understand the concept of capacitive voltage division and how to measure the output voltage across a capacitor in a capacitive voltage divider circuit.

Theory Behind Capacitive Voltage Divider

A capacitive voltage divider is a circuit configuration that uses two capacitors in series to divide the input voltage into smaller output voltages. The output voltage across one of the capacitors is determined by its capacitance, and the total capacitance in the series circuit influences this value. This method is widely used in signal processing and power electronics.

The output voltage (\( V_{out} \)) across the second capacitor (\( C_2 \)) in a capacitive voltage divider is calculated using the following formula:

V_{out} = V_{in} * (C_2 / (C_1 + C_2))

Where:

• \( V_{in} \) = Input voltage
• \( C_1 \) = Capacitance of the first capacitor
• \( C_2 \) = Capacitance of the second capacitor

Components Required

• BreadBoard PowerSupply
• Jumper cables
• BreadBoard
• Oscilloscope
• Signal Generator
• Multimeter
• 10µF Electrolytic Capacitor
• 22µF Electrolytic Capacitor

Circuit Diagram for Capacitive Voltage Divider

Below is the circuit diagram for the capacitive voltage divider:

In the diagram:

• The input voltage (\( V_{in} \)) is applied across the series combination of \( C_1 \) and \( C_2 \).
• The output voltage (\( V_{out} \)) is measured across \( C_2 \).

Steps in the Capacitive Voltage Divider Experiment

1. Set up the circuit on a breadboard according to the circuit diagram.
2. Connect the signal generator to provide a sinusoidal input voltage (e.g., 5V peak-to-peak at 1 kHz).
3. Connect the oscilloscope probes across \( C_2 \) to measure \( V_{out} \).
4. Turn on the signal generator and observe the waveform on the oscilloscope.
5. Record the measured \( V_{out} \) and compare it with the calculated value using the formula provided above.
6. Repeat the experiment with different values of \( C_1 \) and \( C_2 \) to explore the relationship between capacitance and output voltage.

Results of Capacitive Voltage Divider Experiment

In this experiment, the expected results are based on the formula for the capacitive voltage divider:

V_{out} = V_{in} * (C_2 / (C_1 + C_2))

For example, if \( V_{in} = 5V \), \( C_1 = 10 \, \mu F \), and \( C_2 = 20 \, \mu F \), we can calculate the output voltage across \( C_2 \) as follows:

Substitute the values into the formula:

V_{out} = 5 * (20 / (10 + 20)) = 5 * (20 / 30) = 5 * 0.6667 = 3.33V

Therefore, the expected output voltage (\( V_{out} \)) across \( C_2 \) would be 3.33V. You can compare this calculated value with the measured value obtained using the oscilloscope to verify the accuracy of your setup.

When performing this experiment with different capacitance values, you should observe that the output voltage changes in proportion to the capacitance ratio between \( C_1 \) and \( C_2 \). A larger \( C_2 \) relative to \( C_1 \) will result in a higher \( V_{out} \), while a smaller \( C_2 \) will yield a lower output voltage.

Conclusion on Capacitive Voltage Divider

This experiment successfully demonstrates the principle of voltage division using capacitors. By varying the capacitance values, the output voltage across the capacitors can be controlled. This principle is applicable in a variety of electronic circuits where precise voltage levels are necessary for signal processing and power management.