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.

Bus voltage (V)

Peak DC bus voltage at turn-on.

NTC cold resistance (Ω)

Cold (zero-power) resistance of the NTC limiter.

Load resistance (Ω)

Effective series resistance of the charging load.

Estimate the peak inrush current of a rectified supply limited by an NTC thermistor in series with the load. 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]

Limited inrush current (A)

Peak current at the first charging instant.

• Power-supply ripple, hold-up, inrush, efficiency, and loss calculations depend on line range, load transient, switching mode, capacitor bias and ESR, rectifier conduction interval, control limits, temperature, and component tolerance. Safety, stability, EMI, and fault behavior require separate verification.
• 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.

• NTC Inrush Peak

  Compute the peak inrush current through an NTC inrush limiter as the bus voltage divided by the NTC cold resistance.

• Display Backlight Current

  Calculate average backlight supply current from measured electrical power and supply voltage.

• ESD Human Body Model Current

  Estimate idealized HBM short-circuit peak current from charging voltage and the 1500-ohm series resistor; not a substitute for a JS-001 waveform test.