A **Pi-network** is a low-pass matching circuit made of two capacitors and an inductor arranged in a “π” shape. It transforms impedance between a source and load while also providing harmonic suppression.

This calculator computes component values for matching a given source resistance to a load resistance at a specific frequency.

The typical topology:

• Capacitor C₁ from source to ground
• Inductor L in series
• Capacitor C₂ from load to ground

Calculations assume purely resistive source and load impedances. The quality factor (Q) is determined by the ratio of impedances: \[ Q = \sqrt{\left|\frac{R_{\text{high}}}{R_{\text{low}}} - 1\right|} \] From that, we calculate: \[ X_L = Q \cdot R_{\text{low}}, \quad X_C = \frac{R_{\text{high}}}{Q} \] Then: \[ L = \frac{X_L}{2\pi f}, \quad C = \frac{1}{2\pi f X_C} \]

Pi-networks are often used in tube amplifier outputs, antenna tuners, and harmonic filtering.