1. What is an LC Low Pass Filter?

An LC low pass filter is an electronic circuit consisting of an inductor (L) and capacitor (C) that allows signals with a frequency lower than the cutoff frequency to pass through while attenuating higher frequencies.

2. How Does the Calculator Work?

The calculator uses the LC filter cutoff frequency formula:

Where:

• \( f_c \) — Cutoff frequency in Hz
• \( L \) — Inductance in Henries (H)
• \( C \) — Capacitance in Farads (F)
• \( \pi \) — Mathematical constant (~3.14159)

Explanation: The cutoff frequency is the point where the filter begins to attenuate the input signal, typically defined as the -3dB point.

3. Importance of Cutoff Frequency

Details: The cutoff frequency determines the filter's operating range and is crucial for designing circuits that need to block or pass specific frequency ranges.

4. Using the Calculator

Tips: Enter inductance in Henries and capacitance in Farads. Both values must be positive numbers. Common values range from microhenries (µH) to millihenries (mH) for inductors, and picofarads (pF) to microfarads (µF) for capacitors.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between LC and RC low pass filters?
A: LC filters use inductors and capacitors while RC filters use resistors and capacitors. LC filters are more efficient for higher power applications.

Q2: Can I use this for audio applications?
A: Yes, LC filters are commonly used in audio applications, especially in crossover networks for speakers.

Q3: What happens at the cutoff frequency?
A: The output signal is attenuated by 3dB (about 70.7% of the input voltage) at the cutoff frequency.

Q4: How does component tolerance affect the result?
A: Real components have tolerances (typically 5-20%) which will affect the actual cutoff frequency.

Q5: What's the roll-off rate of an LC low pass filter?
A: A basic LC low pass filter has a roll-off rate of -40dB per decade (second-order filter).