1. What is DC Voltage Drop?

Definition: DC voltage drop is the reduction in voltage in an electrical circuit caused by the resistance of conductors.

Purpose: This calculator helps determine the voltage loss in DC electrical systems to ensure proper equipment operation and efficiency.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( VD \) — Voltage drop (volts)
• \( \rho \) — Resistivity of conductor material (ohm-m)
• \( L \) — Length of cable (meters)
• \( I \) — Current flowing through cable (amps)
• \( A \) — Cross-sectional area of conductor (m²)

Explanation: The formula accounts for both outgoing and return paths (hence the factor of 2), material resistance, current load, and conductor size.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical devices receive adequate voltage, prevents power loss, and maintains system efficiency.

4. Using the Calculator

Tips: Enter the conductor resistivity (default 1.68×10⁻⁸ ohm-m for copper), cable length, current, and conductor cross-sectional area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is there a factor of 2 in the formula?
A: The factor accounts for both the outgoing and return paths in a DC circuit (total conductor length is twice the cable length).

Q2: What's a typical resistivity value for copper?
A: Copper has a resistivity of about 1.68×10⁻⁸ ohm-m at 20°C. For aluminum, use 2.65×10⁻⁸ ohm-m.

Q3: What's an acceptable voltage drop?
A: Generally, voltage drop should be less than 3% for power circuits and 5% for lighting circuits of the supply voltage.

Q4: How does temperature affect the calculation?
A: Higher temperatures increase resistivity. For precise calculations, use resistivity values at operating temperature.

Q5: Can I use this for AC circuits?
A: No, AC circuits require additional factors like power factor and reactance. Use an AC voltage drop calculator instead.