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.

Drain current (A)

Required number input.

Gate overdrive (V)

Required number input.

Estimate long-channel saturated MOSFET small-signal transconductance from drain current and gate overdrive, neglecting channel-length modulation. 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]

Transconductance (S)

The resulting transconductance returned as a number.

• MOSFET threshold voltage is not a recommended fully-on gate voltage. Conduction and switching loss depend on gate drive, charge plateaus, current, drain voltage, switching speed, temperature, package parasitics, reverse recovery, dead time, and thermal conditions.
• 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.

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