1. What is Characteristic Impedance?

The characteristic impedance (Z₀) of a transmission line is the ratio of voltage to current in a traveling wave. It's determined by the geometry and materials of the cable and is crucial for impedance matching in RF systems.

2. How Does the Calculator Work?

The calculator uses the characteristic impedance equation:

Where:

• \( Z_0 \) — Characteristic impedance (Ω)
• \( L \) — Inductance per unit length (H/m)
• \( C \) — Capacitance per unit length (F/m)

Explanation: The equation shows that impedance increases with higher inductance and decreases with higher capacitance.

3. Importance of Characteristic Impedance

Details: Proper impedance matching prevents signal reflections, maximizes power transfer, and reduces standing waves in transmission lines.

4. Using the Calculator

Tips: Enter inductance in henries per meter (H/m) and capacitance in farads per meter (F/m). Both values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for cable impedance?
A: Common values are 50Ω (RF systems), 75Ω (video cables), and 300Ω (twin-lead antennas).

Q2: How does frequency affect characteristic impedance?
A: For ideal transmission lines, Z₀ is frequency-independent. Real cables may show variation at very high frequencies.

Q3: What happens when impedance is mismatched?
A: Mismatches cause signal reflections, resulting in power loss and potential signal distortion.

Q4: Can this calculator be used for twisted pair cables?
A: Yes, as long as you know the L and C per unit length values.

Q5: How is characteristic impedance measured?
A: It can be measured using time-domain reflectometry (TDR) or calculated from L and C values.