Filter & Resonance
⚡ Electrical-Electronics · RC/RL cutoff frequency and LC resonant frequency calculation
Frequency-selective circuits (filters and resonant circuits) are fundamental to signal processing and communication systems. This tool covers three basic configurations:
- RC filter: a first-order low-pass filter made of a resistor and capacitor. At the cutoff frequency (fc), the output amplitude drops to 70.7% (−3 dB) of the input amplitude.
- RL filter: an alternative first-order filter made of a resistor and inductor — similar behavior, different components.
- LC resonance: the circuit formed together by an inductor and capacitor makes the impedance purely resistive at a specific frequency (f₀) — this underlies many applications, from channel selection in radio receivers to oscillator design.
Application area: these three basic building blocks are also the starting point for more complex filter designs (multi-stage filters such as Butterworth or Chebyshev).
This tool's calculation logic has been checked against a hand-computed numerical verification test. Test source: src/lib/calc/rlc.test.ts.
- [5] Alexander, Charles K. and Sadiku, Matthew N. O.. Fundamentals of Electric Circuits, 7 ed.. McGraw-Hill, 2021. ↗
Filter & Resonance — EngineersLab calc card
Formula: RC: fc=1/(2πRC), LC: f0=1/(2π√LC)
Sources: [5] Fundamentals of Electric Circuits
Tool version: 1.0.0 · Date:
Source URL: https://engineerslab.com.tr/en/araclar/rlc
Results are for educational and preliminary-sizing purposes; final engineering design decisions must reference the relevant standards and a licensed engineer's approval.