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.

Collector current (A)

Required number input.

DC current gain

Required number input.

Calculate BJT base current. 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]

Base current (A)

The resulting base current returned as a number.

• BJT calculations using a fixed current gain or junction drop are operating-point approximations. Gain, Early effect, saturation voltage, leakage, temperature, frequency, bias network loading, and safe operating area vary by device and 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.

• BJT Collector Current

  Calculate BJT collector current.

• BJT Early Voltage Effect

  Estimate collector current at a new collector-emitter voltage using the linear Early-effect model at fixed base drive.

• BJT Emitter Current

  Calculate BJT emitter current.