BJT Common-Emitter Current Gain Calculator
Convert the common-base current gain (alpha) to the common-emitter current gain (beta) via beta=alpha/(1-alpha) with alpha in (0,1) exclusive, dimensionless. Full double precision without premature rounding; handles near-1 cancellation by checking 1-alpha finite and non-zero and beta finite, reporting numeric_overflow for extreme alpha. Ideal transistor relation neglecting recombination and series resistance; invalid for alpha<=0 or >=1.
Description
Convert common-base current gain alpha into common-emitter current gain beta.
Convert the common-base current gain (alpha) to the common-emitter current gain (beta) via beta=alpha/(1-alpha) with alpha in (0,1) exclusive, dimensionless. Full double precision without premature rounding; handles near-1 cancellation by checking 1-alpha finite and non-zero and beta finite, reporting numeric_overflow for extreme alpha. Ideal transistor relation neglecting recombination and series resistance; invalid for alpha<=0 or >=1.
When to use BJT Common-Emitter Current Gain Calculator
- Convert common-base current gain alpha into common-emitter current gain beta.
- Compare fabrication or device scenarios while holding coefficients and unit conventions constant.
- Check a hand calculation before moving to a higher-fidelity process, circuit, or TCAD model.
How the calculation works
Small changes in alpha near one create large changes in beta; alpha 0.99 corresponds to beta 99.
β = α/(1−α) Interpreting the result
Small changes in alpha near one create large changes in beta; alpha 0.99 corresponds to beta 99.
Assumptions and limitations
- The identity relates terminal current gains at the same operating point and does not predict their bias, frequency, or temperature dependence.
- Use parameters measured for the same material, geometry, temperature, and operating regime whenever the result informs engineering work.