🔍 Key Concepts

• BJT transistor operation (base, collector, emitter currents) • Difference between active region and saturation region • What happens to collector–emitter voltage (Vce) when a transistor saturates

💭 Think About

• Think about what happens to the collector–emitter voltage when a transistor is used like a switch in the ON state. How does that affect collector current? • Which parameter (Alpha, Beta, or currents) directly describes the physical state of the transistor’s junctions being forward biased? • In saturation, is the transistor’s current limited more by the transistor itself or by the external circuit (load and supply)?

✅ Before You Answer

• Recall that in saturation, both the base–emitter and base–collector junctions are forward biased. • Ask yourself: in that condition, what mainly sets the collector current: the transistor gain (Alpha/Beta) or the external circuit? • Match the description of that condition to the choice that talks about collector current behavior, not just gain parameters.