In this post, you will learn about bipolar junction transistor (BJT) active region. Also after this, links for the other two operation regions are provided immediately.
In active region the transistor is bias so that the base (B) measures a higher potential difference (Pd) to the emitter (E) but lower than the collector (C) to the emitter (E). In this region the transistor is always active. This is the biasing mode or region which transistor amplifiers use for their operations.
The below circuits explain and illustrate the operations of the Active regions for both NPN bipolar junction transistor (BJT) and PNP bipolar junction transistor (BJT). The resistor R in the circuits limits the current that will pass through the Light Emitting Diode (LED).
Apart from the BJT active region, below are links to the other two operation region of bipolar junction transistor (BJT). That is; cutoff (FULLY OFF) region and saturation (FULLY ON) region.
CUTOFF REGION (FULLY OFF)
In Bipolar Junction Transistor (BJT) cut off region or fully off region, the transistor is bias in such a way that both junctions are reverse so that no current will pass from the emitter (E) to the collector (C). In this mode, the transistor is in OFF mode.… Read more here> BJT Cutoff Region
SATURATION REGION (FULLY ON)
A transistor is said to be saturated (Fully ON) when it is biased in such a way that current passes from the Emitter (E) to the Collector (C). In NPN and PNP bipolar junction transistors (BJTs), connecting the base (B) to the collector (C) makes the PN-junction from the base (B) to the emitter (E) to be forward bias…..Read more here> BJT Saturation Region