1. What is a Length of Wire Calculator?

Definition: This calculator determines the length of wire based on its electrical resistance, cross-sectional area, and resistivity.

Purpose: It helps electricians, engineers, and students calculate wire lengths needed for specific resistances in electrical circuits.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( L \) — Length of wire (meters)
• \( R \) — Resistance (ohms)
• \( A \) — Cross-sectional area (m²)
• \( \rho \) — Resistivity (ohm-m)

Explanation: The resistance multiplied by cross-sectional area gives the numerator, which is divided by the material's resistivity to determine length.

3. Importance of Wire Length Calculation

Details: Accurate wire length calculations ensure proper circuit design, voltage drop management, and material cost estimation.

4. Using the Calculator

Tips: Enter the resistance in ohms, cross-sectional area in m², and resistivity (default 1.68×10⁻⁸ ohm-m for copper). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is resistivity?
A: Resistivity is a material property that quantifies how strongly it opposes electric current (e.g., copper: 1.68×10⁻⁸ ohm-m).

Q2: How do I find cross-sectional area?
A: For round wires: \( A = πr² \) where r is radius, or \( A = π(d/2)² \) where d is diameter.

Q3: What's the resistivity of common materials?
A: Copper: 1.68×10⁻⁸, Aluminum: 2.65×10⁻⁸, Silver: 1.59×10⁻⁸ ohm-m.

Q4: Can I use this for AWG wire sizes?
A: Yes, but first convert AWG to cross-sectional area (available in standard tables).

Q5: Does temperature affect the calculation?
A: Yes, resistivity changes with temperature, but this calculator uses room temperature values.