RC Filter Signal Smoothing Experiment

Objective

The objective of this experiment is to design and implement an RC (Resistor-Capacitor) filter to smooth out an input signal, demonstrating the principles of low-pass filtering.

Components Required

• 1 x Resistor (R)
• 1 x Capacitor (C)
• 1 x Signal Generator (to produce a square wave or any noisy signal)
• 1 x Oscilloscope
• 1 x Power Supply
• Connecting Wires
• Breadboard (optional)

Theory

RC filters are commonly used to smooth out signals by attenuating high-frequency noise. In a low-pass RC filter, the resistor (R) and capacitor (C) work together to create a time constant that determines how quickly the capacitor charges and discharges. The output voltage across the capacitor will follow the input signal but with reduced amplitude at higher frequencies.

The cutoff frequency \( f_c \) can be calculated using the formula:

• \( f_c = \frac{1}{2\pi RC} \)
• Where: \( R \) = resistance (in ohms), \( C \) = capacitance (in farads).

Circuit Diagram

Experimental Setup

1. Connect the resistor and capacitor in series according to the circuit diagram.

2. Connect the input from the signal generator to the series combination of the resistor and capacitor.

3. Connect the output across the capacitor.

4. Use the oscilloscope to measure the input and output signals.

Procedure

1. Set up the RC filter circuit according to the circuit diagram.
2. Apply a square wave signal from the signal generator to the input.
3. Observe the input signal on the oscilloscope and note its characteristics (frequency and amplitude).
4. Observe the output signal across the capacitor and compare it with the input signal.
5. Vary the resistance and capacitance values and observe how the output signal changes.

Results and Observations

Document the characteristics of the input and output signals, noting how well the RC filter smooths out the signal and the effect of different component values on the performance of the filter.

Conclusion

This experiment demonstrates the operation of an RC filter in smoothing out an input signal. The performance of the filter is influenced by the values of the resistor and capacitor, allowing for tuning to desired cutoff frequencies.