1. What is a Capacitor Value Calculator?

Definition: This calculator determines the capacitance value needed to achieve a specific reactance at a given frequency in an AC circuit.

Purpose: It helps electronics engineers, technicians, and hobbyists select the right capacitor for filter circuits, tuning circuits, and impedance matching.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( C \) — Capacitance (farads)
• \( f \) — Frequency (Hz)
• \( X_c \) — Capacitive reactance (ohms)
• \( \pi \) — Pi constant (~3.14159)

Explanation: The formula calculates the capacitance needed to present a specific reactance at a given frequency in an AC circuit.

3. Importance of Capacitance Calculation

Details: Proper capacitor selection ensures correct circuit operation in applications like filters (blocking/ passing specific frequencies), power factor correction, and timing circuits.

4. Using the Calculator

Tips: Enter the frequency in Hz and desired capacitive reactance in ohms. Both values must be > 0. The result is in farads (use metric prefixes like μF, nF, pF for practical values).

5. Frequently Asked Questions (FAQ)

Q1: Why does reactance change with frequency?
A: Capacitive reactance is inversely proportional to both frequency and capacitance (\(X_c = 1/(2\pi f C)\)).

Q2: What's a typical reactance value?
A: This depends on application - might range from a few ohms in power circuits to thousands of ohms in signal circuits.

Q3: How do I convert farads to microfarads?
A: Multiply by 1,000,000 (1F = 1,000,000μF). The calculator shows farads; most practical capacitors are μF or smaller.

Q4: Does this work for DC circuits?
A: No, capacitors block DC (infinite reactance at 0Hz). This calculator is for AC circuits only.

Q5: What if I need to calculate reactance from capacitance?
A: Use the inverse formula: \(X_c = 1/(2\pi f C)\).