# Coax Cable Calculator (Impedance-Inductance-Capacitance)

Impedance (ohms):

Inductance (nano henries):

Cutoff Frequency (GHz):

## Introduction

Coaxial cables are a common choice for transmitting electrical signals due to their excellent shielding and impedance characteristics. To work effectively with coaxial cables, it’s important to calculate various parameters such as impedance, capacitance, inductance, and cutoff frequency. In this article, we’ll introduce you to a Coaxial Cable Calculator that simplifies these calculations. Whether you’re an engineer, technician, or hobbyist, this tool will help you ensure that your coaxial cable setups meet your specific requirements.

## How to Use

Using the Coaxial Cable Calculator is straightforward. Follow these steps:

1. Outer Diameter (D): Enter the outer diameter of your coaxial cable in millimeters.
2. Inner Diameter (d): Provide the inner diameter of the cable in millimeters.
3. Relative Permittivity (εr): Input the relative permittivity of the cable’s dielectric material.

Once you’ve filled in these fields, click the “Calculate” button to get the results.

## Formula

The formula used for calculating the impedance (Z) of the coaxial cable is as follows:

Z = 138 * log(D/d) / sqrt(εr)

Where:

• Z is the impedance in ohms.
• D is the outer diameter of the cable.
• d is the inner diameter of the cable.
• εr is the relative permittivity.

## Example

Let’s say you have a coaxial cable with an outer diameter of 8 mm, an inner diameter of 4 mm, and a relative permittivity of 2.3. Using the formula, the impedance can be calculated as follows:

Z = 138 * log(8/4) / sqrt(2.3) ≈ 60.44 ohms

The calculator will give you the same result.

## FAQs

Q1: What is coaxial cable impedance?

A1: Coaxial cable impedance represents the opposition to the flow of alternating current in the cable. It is typically expressed in ohms and plays a crucial role in signal transmission.

Q2: Why is impedance important in coaxial cables?

A2: Impedance matching is essential for minimizing signal loss and ensuring efficient signal transfer in coaxial cables. Mismatched impedance can lead to signal reflections and loss of signal quality.

Q3: What is relative permittivity (εr)?

A3: Relative permittivity, also known as dielectric constant, measures how well a material can store electrical energy. It affects the capacitance and velocity of signal propagation in coaxial cables.

## Conclusion

The Coaxial Cable Calculator is a valuable tool for anyone working with coaxial cables. It simplifies the process of calculating impedance, capacitance, inductance, and cutoff frequency. By using this tool, you can optimize your coaxial cable setups for various applications, ensuring efficient signal transmission and minimizing signal loss.