RC Low-Pass Filter Calculator





Formulas

The formulas to calculate the cutoff frequency and voltage ratio of an RC low-pass filter are:

Cutoff Frequency:

\[ f_c = \frac{1}{2\pi RC} \]

Voltage Ratio at Cutoff Frequency:

\[ \frac{U_2}{U_1} = \frac{1}{\sqrt{2}} \]

Where:

What is an RC Low-Pass Filter?

An RC low-pass filter is an electronic circuit consisting of a resistor (R) and a capacitor (C) connected in series. It allows low-frequency signals to pass through while attenuating high-frequency signals. The cutoff frequency is the frequency at which the output voltage is reduced to 70.7% of the input voltage.

Example Calculation

Let's assume the following values:

Step 1: Calculate the cutoff frequency:

\[ f_c = \frac{1}{2\pi \times 5.6 \times 10^3 \times 4.7 \times 10^{-6}} \approx 6.04 \, Hz \]

Step 2: Voltage ratio at cutoff frequency:

\[ \frac{U_2}{U_1} = \frac{1}{\sqrt{2}} \approx 0.707 \]