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When does a NPN transistor go into saturation?
9 Answers. 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. Consider this Common Emitter Amplifier circuit.
How much voltage drop across NPN BJT C & E?
In any event, at no time was the transistor driven into saturation, which would result in a collector-emitter voltage on the order of 0.5 volts or less. Repeat this experiment with a 1 kΩ resistor between the collector and Vcc and raise Vcc to 10 V so you can get 10 mA of collector current at saturation.
Why does a BJT transistor have to be saturated?
BJT transistor will be saturated the moment the Ic will not follow the linear relation of: I c = H F E ∗ I b. Thus all we have to do is to limit the Ic from reaching this value. Since I b is determined by the value of the resistor connected to the base and the driving voltage on its other end, it is easy to force I b to any value.
What’s the voltage between a BJT and VBE?
This is what I know about NPN BJTs (Bipolar Junction Transistors): Vbe is the voltage between Base-Emitter, and, like any diode, is usually around 0,65V. I don’t remember about Vec, though.
What kind of amplifier is used in a NPN transistor?
If a suitable DC “biasing” voltage is firstly applied to the transistors Base terminal thus allowing it to always operate within its linear active region, an inverting amplifier circuit called a single stage common emitter amplifier is produced. One such Common Emitter Amplifier configuration of an NPN transistor is called a Class A Amplifier.
How does saturate depend on the type of transistor?
How much current will depend on the type of transistor. ‘saturation’ has to do with how many of the charge carriers in the base region can make it into the collector region. Some will come from the base terminal, but many more will come into the base region from the emitter region.
Which is more positive in a bipolar NPN transistor?
Also the Collector supply voltage is positive with respect to the Emitter ( V CE ). So for a bipolar NPN transistor to conduct the Collector is always more positive with respect to both the Base and the Emitter.