BJT Flashcards
(19 cards)
What type of bin is needed to get NPN and PNP to operate for ac amplification?
DC biasing
What is a transistor?
A transistor is a three layer semiconductor device consisting of either two and and one P type layers or 2P and 1 N type layers
What does BJT stand for
Bipolar Junction transistor
Speak on the doping levels of the layers
The Itza is heavily doped. The base is lightly doped, and the collector is moderately doped.
What does the term bipolar reflect?
The fact that both the holes and the electrons take part in the injection process into the oppositely polarized material. If only one carrier took part it would be considered a unipolar device
What are some applications of BJT transistors?
Amplification of signals and two act as a switch to control circuits
Does the current combine or separate in a NPN transistor?
Combine
 what does the direction of the emitter arrow represent?
The flow of conventional current
How are the PN junctions of the transistor oriented?
1 PM junction is reversed biased while the other is forward biased
What are the differences between NPN and PNP transistors
Firstly their doped layers are oriented differently
Secondly
In NPN transistor current flows into the base and collector and flows out of the emitter
Whilst in PNP it flows into the emitter and out of the base and collector.
Describe the active region of a BJT
In the active region, the collector base junction is reversed while the base emits junction is forward biased
CB REVERSE
Girl if yuh active B-E FORWARD
Which car is at zero in the active region?
The emitter current
Which current is at zero in the cut off region
The collector current is at zero in the cut of region
Define the cut off region of a BJT
In the cut off region, the collector base and the emitter junctions about resisted
They both reversed out
Describe the saturation region of the BJT
Both CB and BE are forward biased
What mood do you place the transistor in for it to operate as an common emitter amplifier?
The active mode where the collector base junction is in reverse and the emitter junction is forward
Come active
In what mood do you please transistor for linear application purposes?
Cut off mode
What mood do you put a BJT in to get it to function like a switch?
Saturation mode
