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.

Reactance (Ω)

Reactance magnitude at the operating frequency.

ESR (Ω)

Series resistance modeling the losses.

Derive the quality factor of a component from its reactance and equivalent series resistance. 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]

Quality factor

Dimensionless quality factor.

• Bandwidth-to-Q relationships usually assume a lightly coupled, approximately second-order resonance and a specified bandwidth convention. Loading, multiple resonances, loss variation, and measurement method can change the inferred Q.
• 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.

• ESR From Q

  Derive the equivalent series resistance of a component from its reactance and quality factor.

• ESR From Dissipation Factor

  Compute equivalent series resistance as dissipation factor / (2 x PI x frequency x capacitance).

• Crystal Quality Factor

  Calculate a crystal motional branch's unloaded series Q from series frequency, motional inductance, and series resistance.