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.

Series resonance frequency (Hz)

Required number input.

Motional inductance (H)

Required number input.

Motional series resistance (Ω)

Required number input.

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

Unloaded series Q

The resulting unloaded series q returned as a number.

• Oscillator estimates use nominal component values and simplified resonator models. Load capacitance, parasitics, drive level, startup margin, phase noise, temperature, aging, pulling, and amplifier nonlinearities determine the realized frequency and stability.
• 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.

• Crystal Series Resistance

  Infer crystal motional series resistance from series frequency, motional capacitance, and unloaded series quality factor.

• Inductor Q at Frequency

  Calculate series-model inductor quality factor Q=2πfL/R from inductance and effective series resistance at the specified frequency. Core and skin-effect losses should be included in the supplied resistance.

• Crystal Motional Inductance

  Calculate motional inductance from a crystal's series-resonant frequency and motional capacitance.