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Capacitance & Inductance Calculator

Calculate reactance, impedance, resonant frequency, and time constants for reactive components

Reactive Component Calculations

How to Use the Calculator

Getting Started

  • Step 1: Select the type of calculation you need from the available options
  • Step 2: Enter component values using appropriate units (pF to F, nH to H)
  • Step 3: For frequency-dependent calculations, specify the operating frequency
  • Step 4: Click Calculate to get detailed results with step-by-step explanations

Key Reactive Component Concepts

  • Capacitive Reactance: Xc = 1/(2πfC) - Decreases with frequency
  • Inductive Reactance: XL = 2πfL - Increases with frequency
  • Resonance: f₀ = 1/(2π√LC) - When XL = Xc
  • Time Constants: τ = RC (capacitor) or τ = L/R (inductor)

Best Practices

  • Units: Pay attention to component value units (μF, mH, etc.)
  • Frequency Range: Consider component self-resonance at high frequencies
  • Tolerance: Real components have tolerances that affect actual values
  • Temperature: Component values can change with temperature

Professional Guidelines

  • Filter Design: Use resonant frequency calculations for filter design
  • Impedance Matching: Calculate impedance for proper circuit matching
  • Timing Circuits: Use time constants for timing and delay circuits
  • Power Supplies: Consider reactive components in power supply design

Frequently Asked Questions

What's the difference between reactance and impedance?

Reactance is the opposition to AC current by reactive components (capacitors and inductors). Impedance combines both resistance and reactance: Z = √(R² + X²).

How do I calculate the resonant frequency of an LC circuit?

Use f₀ = 1/(2π√LC). At this frequency, inductive and capacitive reactances cancel out, resulting in minimum impedance in a series circuit.

What is a time constant and why is it important?

Time constant (τ) determines how quickly capacitors charge/discharge (τ = RC) or inductors build up current (τ = L/R). It's crucial for timing circuits and transient analysis.

How does frequency affect reactive components?

Capacitive reactance decreases with frequency (Xc ∝ 1/f), while inductive reactance increases with frequency (XL ∝ f). This makes them useful for frequency-selective circuits.

What happens at resonance in an LC circuit?

At resonance, XL = Xc, so reactive components cancel out. In a series circuit, impedance is minimum (only resistance remains). In parallel, impedance is maximum.

How do I account for component tolerances in my calculations?

Real components have tolerances (±5%, ±10%, etc.). For critical applications, calculate worst-case scenarios using minimum and maximum component values.

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