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What happens in the saturation region of a transistor?
A transistor in saturation mode acts like a short circuit between collector and emitter. In saturation mode both of the “diodes” in the transistor are forward biased. Because the junction from base to emitter looks just like a diode, in reality, VBE must be greater than a threshold voltage to enter saturation.
What happens in saturation region?
Saturation region This is the region in which transistor tends to behave as a closed switch. The transistor has the effect of its collector and Emitter being shorted. The collector and Emitter currents are maximum in this mode of operation.
What is saturation region in transistors?
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.
Why does the collector current decrease when the transistor is operated in the saturation region?
In saturation many electrons make it to the base instead of being pulled into the collector. That makes the base current larger and the collector current smaller. When the base current is kept constant that would result in a smaller collector current.
How do you know if BJT is in active region?
For the BJT to operate in the active region, the condition is that the base-emitter junction should be forward-biased while the base-collector junction is reverse-biased. In this region, IC almost remains constant for a given value of IB.
What happens when transistor operates in saturation region for?
Above 2.9V the the transistor goes into saturation as the voltage between the Collector (green line) and Emitter (blue line) drops below 0.2V, causing β to reduce and requiring more Base current (magenta line) to maintain current through R E.
How much C-E does a saturated transistor have?
A saturated transistor typically has around 200mV C-E, but that also can vary a lot by the design of the transistor and the current. One artifact of saturation is that the transistor will be slow to turn off. There are extra “unused” charges in the base that take a little while to drain out.
How does a saturated NPN transistor work?
Since the collector of a NPN will act like a current sink and in saturation the external circuit isn’t giving it as much current as it could pass, the collector voltage will go as low as it can. A saturated transistor typically has around 200mV C-E, but that also can vary a lot by the design of the transistor and…
Which is the active region of a transistor?
The transistor operates in active region when the emitter junction is forward biased and collector junction is reverse biased. In the active state, collector current is β times the base current, i.e., This is the region in which transistor tends to behave as a closed switch. The transistor has the effect of its collector and Emitter being shorted.