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When the forward saturation in Bipolar junction transistor occurs?
Wiki User
∙ 13y ago
Forward saturation in a BJT occurs when the ratio of collecter-emitter current and base-emitter current reaches hFe or dc beta. A that point, the BJT is no longer operating in linear mode.
Wiki User
∙ 13y ago
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What are the uses of BJT?
Bipolar junction transistors has two junctions base emitter junction, base collector junction. Accordingly there are four different regions of operation in which either of the two junctions are forward biased reverse biased or both. But the BJT can be effectively operated in there different modes according to the external bias voltage applied at each junction. i.e. Transistor in active region, saturation and cutoff. The other region of operation of BJT is called as inverse active region.
What are characteristics of transistors?
These are the Key characteristic specification of a Bipolar Junction transistor Vceb Breakdown voltage Vcesat Saturation voltage Vbe Sat Maxximum Forward current Leakage Current Power dissipation Thermal resistance theta-JC and theta-JA Hfe Polarity NPN or PNP Frequency
What happen if the series resistor in a forward-biased p-n junction is short-circuited?
The junction (diode or transistor) will be destroyed.
Why a transistor can be operated in active region?
a transistor can only work in active region cox in active region collector base junction is in reverse bias and emitter base junction is in forward bias.
What is the reason for reverse saturation current?
its simple.reverse saturation current is because of the flow of minority carriers across the junction when the bias is changed suddenly from forward to reverse.this is why it doesnt depend on forward bias
How can you tell if a transistor is a saturated bipolar transistor?
Saturation mode is the condition wherein the base-collector junction becomes forward biased, as opposed to reverse-biased in the case of active mode. It is necessary for the base-emitter junction to be forward biased, and thus a base current will be flowing. Typically the base current is much higher than it would be in active mode, and the effective Hfe of the transistor drops rapidly. These conditions apply to both NPN and PNP transistors equally. In practice, the collector-emitter voltage of a transistor in saturation is very low, less than 0.1 V, but this depends on the specific transistor. Some high-power transistors will only saturate to 0.4 V. Saturated transistors sometimes begin to overheat or smoke, although saturation is not always a fault condition. When a transistor is used as a switch, this means it alternates exclusively between cutoff and saturation.
What are the uses of BJT?
Bipolar junction transistors has two junctions base emitter junction, base collector junction. Accordingly there are four different regions of operation in which either of the two junctions are forward biased reverse biased or both. But the BJT can be effectively operated in there different modes according to the external bias voltage applied at each junction. i.e. Transistor in active region, saturation and cutoff. The other region of operation of BJT is called as inverse active region.
A transistor is in active region when?
a transistor in active region when emitter junction is forward biased nd collector junction is reverse biased
What bias conditions must be present for the normal operation of a transistor ampilifier?
Assuming you mean a bipolar junction transistor (BJT): 1. Reverse bias on the collector-base junction. 2. Forward bias on the base-emitter junction, that is 3. Sufficient to give the correct operating point of collector voltage/collector current.
How do you know if a transistor is a PNP or an NPN?
To know if a transistor is PNP or an NPN,the following should be verified:For a PNP transistor, the base-collector junction is forward biased while the base-emitter junction is reversed biased.For an NPN transistor, the base-emitter junction is forward biased while the base -collector junction is reversed biased.
What are characteristics of transistors?
These are the Key characteristic specification of a Bipolar Junction transistor Vceb Breakdown voltage Vcesat Saturation voltage Vbe Sat Maxximum Forward current Leakage Current Power dissipation Thermal resistance theta-JC and theta-JA Hfe Polarity NPN or PNP Frequency
How do NPN bipolar junction transistors turn on and off?
In order to bias a bipolar junction transistor on, you need to forward bias the base-emitter junction at the same time you forward bias the collector-emitter junction, and the ratio of collector current over base current must be somewhat less than hFe, the transistor's gain. This is known as saturated, or non-linear mode, operation. In practice, we drive the base much harder than the calculated required current, so as to minimize dependency on varying hFe's for various transistors.Turning the transistor off is a simple matter of eliminating the base current.In the case of the NPN transistor, the base and collector would need to be more positive than the emitter. In the case of the PNP, they would need to be more negative.
What is the biasing technique in transistor for it to be in active region?
For a transistor to be in active region : Base Emitter junction should be forward biased and Emitter collector junction should be reverse biased.
What happen if the series resistor in a forward-biased p-n junction is short-circuited?
The junction (diode or transistor) will be destroyed.
A PNP transistor is connected in a circuit so that the collector-base junction remains reverse biased and the emitter-base junction is forward biased This transistor can be used as a power amplifier?
Yes1
Why a transistor can be operated in active region?
a transistor can only work in active region cox in active region collector base junction is in reverse bias and emitter base junction is in forward bias.
Can you use transistor as a rectifier?
No, a Transistor operates with a modulated direct current. You need 4 Diodes to manufacture a rectifier to deliver direct current at the outlet, with alternating current at the input. A Diode is effectively a one way valve to address one halve of the cycle of the alternating current.
