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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 the normal operating condition of transistor?
The normal operating conditions of a transistor typically involve it being in one of its active regions, such as the active region for bipolar junction transistors (BJTs) or the saturation region for field-effect transistors (FETs). For BJTs, this means the base-emitter junction is forward-biased while the collector-base junction is reverse-biased. For FETs, it involves applying a sufficient gate-source voltage to allow current to flow between the drain and source. Under these conditions, the transistor can amplify signals or switch them effectively.
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
Turn on and off time in bjt?
The turn-on time in a bipolar junction transistor (BJT) refers to the duration it takes for the transistor to switch from the cutoff region (off state) to the saturation region (on state) after a forward bias is applied. Conversely, the turn-off time is the time required for the BJT to switch from saturation back to cutoff after the bias is removed. These times are influenced by factors such as the transistor's internal capacitances, the base drive current, and the collector-emitter voltage. Minimizing these times is crucial for improving the switching speed in high-frequency applications.
What happen if the series resistor in a forward-biased p-n junction is short-circuited?
The junction (diode or transistor) will be destroyed.
What is meant by saturation region active region and cut off region?
In the context of a bipolar junction transistor (BJT), the saturation region refers to the state where both the base-emitter and base-collector junctions are forward-biased, allowing maximum current to flow from collector to emitter. The active region occurs when the base-emitter junction is forward-biased while the base-collector junction is reverse-biased, enabling the transistor to amplify signals. The cutoff region is when both junctions are reverse-biased, resulting in minimal current flow, effectively turning the transistor off. These regions define the operational modes of the transistor in electronic circuits.
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.
What are the normal operating condition of transistor?
The normal operating conditions of a transistor typically involve it being in one of its active regions, such as the active region for bipolar junction transistors (BJTs) or the saturation region for field-effect transistors (FETs). For BJTs, this means the base-emitter junction is forward-biased while the collector-base junction is reverse-biased. For FETs, it involves applying a sufficient gate-source voltage to allow current to flow between the drain and source. Under these conditions, the transistor can amplify signals or switch them effectively.
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.
A transistor is in active region when?
a transistor in active region when emitter junction is forward biased nd collector junction is reverse biased
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
Turn on and off time in bjt?
The turn-on time in a bipolar junction transistor (BJT) refers to the duration it takes for the transistor to switch from the cutoff region (off state) to the saturation region (on state) after a forward bias is applied. Conversely, the turn-off time is the time required for the BJT to switch from saturation back to cutoff after the bias is removed. These times are influenced by factors such as the transistor's internal capacitances, the base drive current, and the collector-emitter voltage. Minimizing these times is crucial for improving the switching speed in high-frequency applications.
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.
