BJT NPN transistors

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Calculate the operating point Q for a common-emitter NPN BJT transistor with voltage divider bias. Check saturation, active region and gain.

Common emitter Divider R1/R2 Point Q (Ic, Vce)

Circuit parameters

See also

Frequently asked questions

How to calculate BJT base resistor?

Rb = (Vcc − Vbe) / Ib. Ib = Ic/hFE. With Ic=100mA, hFE=100, Vcc=5V: Rb ≈ 4.3kΩ.

What is BJT saturation?

Fully on state (switch closed). Vce ≈ 0.2V. Ensure Ib > Ic/hFE × 2 for margin.