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Voltage Drop: Why Your 12 V Arrives at 11

Wire gauge, run length and the 3% rule — the copper math behind dim LEDs and hot connectors.

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Wire Voltage Drop Calculator (AWG & mm²)

Round-trip voltage drop, percent loss and wasted watts for any cable run — copper or aluminium, AWG or metric.

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AWG Wire Size Calculator

Exact diameter, area, resistance and rule-of-thumb ampacity for any AWG gauge — from the ASTM B258 formula, not a lookup.

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Solar Wire Gauge Calculator

PV wire size from Isc with the NEC 1.56× design factor AND a voltage-drop target — returns the AWG that satisfies both.

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DC Fuse Sizing Calculator

Fuse rating from continuous load with headroom factor, snapped to standard sizes and checked against your wire's capacity.

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Ohm's Law Calculator (V, I, R, P)

Enter any two of voltage, current, resistance and power — get the other two with the substituted formula shown step by step.

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Electrical Power Calculator (DC, 1φ, 3φ)

Real, apparent and reactive power for DC, single-phase and three-phase systems with power factor — plus kWh per day.

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