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How does BJT work in saturation region?
The BJT operates in the saturation region when its collector current is not dependent on the base current and has reached a maximum. The condition for this to happen is that both the base-emitter and the base-collector junctions should be forward-biased. Basic BJT circuit with variable VBB and fixed VCC.
How is a BJT transistor driven into saturation?
A transistor goes into saturation when both the base-emitter and base-collector junctions are forward biased, basically. So if the collector voltage drops below the base voltage, and the emitter voltage is below the base voltage, then the transistor is in saturation.
What is saturation region BJT?
The second region is called “saturation”. This is where the base current has increased well beyond the point that the emitter-base junction is forward biased. In fact, the base current has increased beyond the point where it can cause the collector current flow to increase.
How do you calculate BJT mode?
To find out which mode a PNP transistor is in, reverse all of the < and > signs. For example, to put a PNP into saturation VC and VE must be higher than VB. You pull the base low to turn the PNP on, and make it higher than the collector and emitter to turn it off.
What is saturation voltage of BJT?
BJT in Saturation Mode. • When the collector voltage drops below the base voltage, the collector-base junction is forward biased Base current increases so that the current biased. Base current increases, so that the current gain (IC/IB) decreases.
How do you solve BJT saturation?
Lets ASSUME instead that the BJT is in saturation. Thus, we ENFORCE the conditions: VCE = 0.2 V VBE = 0.7 V VCB = -0.5 V Now lets ANALYZE the circuit ! + 0.2 – + 0.7 – + -0.5 – iB iE iC Note that we cannot directly determine the currents, as we do not know the base voltage, emitter voltage, or collector voltage.
How many modes BJT works?
The operational mode of the BJT depends on how the junctions between the regions are biased. Since there are two junctions, the emitter-base junction (EBJ) and the collector-base junction (CBJ), and each of these junctions may be either forward- or reverse-biased, there are four possible modes of operation.
What mode does BJT work in?
With both junctions forward-biased, a BJT is in saturation mode and facilitates high current conduction from the emitter to the collector (or the other direction in the case of NPN, with negatively charged carriers flowing from emitter to collector).