1. What is RC Cutoff Frequency?

The RC cutoff frequency is the frequency at which the output voltage of an RC circuit is reduced to 70.7% (-3dB) of its maximum value. It marks the boundary between the passband and stopband in a simple RC filter.

2. How Does the Calculator Work?

The calculator uses the RC cutoff frequency formula:

Where:

• \( f_c \) — Cutoff frequency in Hertz (Hz)
• \( R \) — Resistance in Ohms (Ω)
• \( C \) — Capacitance in Farads (F)
• \( \pi \) — Mathematical constant (~3.14159)

Explanation: The cutoff frequency is inversely proportional to both the resistance and capacitance values in the circuit.

3. Importance of Cutoff Frequency

Details: The cutoff frequency is crucial in filter design, signal processing, and audio electronics. It determines which frequency components pass through the circuit and which are attenuated.

4. Using the Calculator

Tips: Enter resistance in Ohms (Ω) and capacitance in Farads (F). For common capacitor values, remember that 1μF = 0.000001F, 1nF = 0.000000001F, etc.

5. Frequently Asked Questions (FAQ)

Q1: What happens at the cutoff frequency?
A: At the cutoff frequency, the output signal power is reduced to half (-3dB) of its maximum value, and the phase shift is 45 degrees.

Q2: How does changing R or C affect the cutoff frequency?
A: Increasing either R or C will lower the cutoff frequency, while decreasing them will raise it.

Q3: What's the difference between high-pass and low-pass cutoff?
A: The same formula applies to both, but in a high-pass filter it's the frequency below which signals are attenuated, while in low-pass it's above.

Q4: Can I use this for RL circuits?
A: No, RL circuits use a different formula: \( f_c = R / (2 \pi L) \).

Q5: Why is the cutoff frequency important in audio systems?
A: It helps design crossovers that direct appropriate frequency ranges to different speakers (woofers, tweeters, etc.).