What is a BJT?

2 Answers

Answer :

BJT is a bipolar junction transistor. BJT have three terminal. Base, emitter and collector are the three terminals of BJT. BJT is a current controlled device. NPN and PNP are the two types of BJT.

Answer :

Bipolar Junction Transistor (BJT):

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BJT is a Bipolar device. (Uses both electrons and holes charge carrier for current conduction)
Two Junctions (Emitter junction & collector junction)
Transfer-Resistor (Transistor) (Amplify by transferring signal from lower resistance to higher resistance region)
BJT is minority carrier device.
Three terminal device
Emitter (More doped) (Smaller area)
Base (Thin & lightly doped)
Collector (Less doped)(Larger area)
Two type semiconductor
N-type and P-type
N-type (Electrons are carrier)
P-type (Holes are carrier)
NPN and PNP
Basic function is to amplify current
Use as amplifiers and switches
BJT is a current controlled device.
The input impedance of BJT is low.
Small base current.
Emitter (Emits electrons)
Collector (Collects electrons)
Current gain β = Ic/Ib
The drive circuit of BJT is complex.
Switching speed of BJT is in the range of microseconds means slow switching speed.
BJT is the negative temperature coefficient device.
Conduction losses are low.
Switching losses are high for high frequency.
Applications: computer, mobile phones, audio amplifiers, radio etc.
Active mode (Current amplification)
Cutoff mode (Open switch)
Saturation mode (Close switch)

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Last Answer : An FET is a better chopper than a BJT because it has lower offset voltage

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Last Answer : Yes BJT have internal capacitances.

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Last Answer : In cut-off region of BJT both the emitter-base junction and collector-base junction are reverse biased.

Last Answer : Active region of BJT act as amplifier.

Last Answer : Active , Saturation , Cut-off region of operations in BJT.

Last Answer : Yes BJT have second breakdown problem.

Last Answer : BJT is current controlled device.

Last Answer : BJT have three terminals Base, emitter and collector.

Last Answer : In  BJT  there  is  movement  of   electrons  and  holes   accros  the  junctions  which  is  basicaly  current  flow.

Last Answer : When Q-point is at cut off region means it is just above the horizontal axis VCE

Last Answer : The proper flow of zero signal collector current and the maintenance of the proper collector emmiter voltage during passage of single called as transistor biasing

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Last Answer : BJT control the flow of electron so it is a active device.

Last Answer : No, BJT is a current controlled device .

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Last Answer : Bjt transistor is a type of transistor which  uses both electrons and hole charge carrier.bjts are used as switches and amplifiers.They amplify currents.

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Last Answer : open emitter BJT drive circuit:

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Last Answer : Because the output (collector) current can be controlled by base current.

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Last Answer :  output characteristics of BJT in CE configuration 

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