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.