Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Current (A)

Required number input.

Wire length (m)

Required number input.

Wire resistivity (ohm*mm^2/m)

Required number input.

Cross-section (mm^2)

Required number input.

Compute the round-trip voltage drop along a two-conductor wire run. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Voltage drop (V)

The resulting voltage drop returned as a number.

• Compact electronics formulas omit some combination of tolerances, temperature drift, bandwidth, loading, parasitics, noise spectrum, nonlinearity, clipping, calibration, layout, and device-specific limits. Typical datasheet values are not guaranteed limits.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Wire Power Loss

  Compute the ohmic power dissipated in a round-trip wire run at a given current.

• Battery Internal Impedance

  Estimate DC battery internal resistance from the voltage drop between two load-current operating points measured over a short interval.

• Motor No Load Speed

  Ideal no-load rotational speed from motor speed constant and applied voltage; ignores friction and no-load current drop.