short notes on npn & pnp transisitor..........
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Answer / thowsif_emerson_csm team
NPN Transistor :-
Just as in the case of the PN junction diode, the N
material comprising the two end sections of the NP N
transistor contains a number of free electrons, while the
center P section contains an excess number of holes. The
action at each junction between these sections is the same
as that previously described for the diode; that is,
depletion regions develop and the junction barrier appears.
To use the transistor as an amplifier, each of these
junctions must be modified by some external bias voltage.
PNP Transisitor:-The PNP transistor works essentially the
same as the NPN transistor. However, since the emitter,
base, and collector in the PNP transistor are made of
materials that are different from those used in the NPN
transistor, different current carriers flow in the PNP
unit. The majority current carriers in the PNP transistor
are holes. This is in contrast to the NPN transistor where
the majority current carriers are electrons. To support
this different type of current (hole flow), the bias
batteries are reversed for the PNP transistor.
Is This Answer Correct ? | 14 Yes | 4 No |
Answer / zahid anwar
PNP :
It is a transistor in which n layer is sand witched between
the layer of p type semiconductor .
Movement of holes takes place from emitter to collector
via base in case of common base transistor .
In this case holes are majority in majority .
Diagram
An Arrow
in PNP transistor arrow is in inward direction.
NPN:
It is a bipolar junction transistor in which a p
type semiconductor is sand witched between two n type
semiconductor .
The movement is of electrons from emitter to collector via
base in common base transistor .
In this case electrons are in majority.
Note
NPN transistor is much preferred over PNP because mobility
of electrons is greater than holes or positive charges .
Diagrams
An Arrow
In NPN an arrow on emitter is in outward direction.
Is This Answer Correct ? | 5 Yes | 0 No |
Answer / shubham joshi
During the half of the input signal the potential of base with respect of emitter is less negative as a result current Ic decreases which results increasing in collector voltage Vc .Icr decreses hence mathematically Ve increases bcoz collector is joined at low potential during the negative half of a input signal . the low potential of base decrease hence potential difference Vbe increase .in this way opposite signals are obtained in diff. half cycle of input signal and having a phase difference of 180 between input and output centre.
Is This Answer Correct ? | 2 Yes | 0 No |
Basics Of transistor
In NPN transistor a P type semiconductor is dopped in
between two N type semiconductors,
whereas in PNP a N type semiconductor is dopped in between
two P type
semiconductors,
as per diagrams in NPN an arrow is there on emitter in
outward direction,
whereas in PNP transistor arrow is in inward direction
Ex-
BC -548-NPN B→ C →E→
BC 558- PNP B ← C ← E←
Is This Answer Correct ? | 3 Yes | 2 No |
Answer / er. nitin yadav
In npn transistor a p type semiconductor is sandwitched in
bitween two n type semiconductors,whereas in pnp a n type
semiconductor is sandwitched in bitween two p type
semiconductors, in diagrams in npn an arrow is ther on
emitter in outward direction,whereas in pnp transistor arrow
is in inward direction
Is This Answer Correct ? | 3 Yes | 3 No |
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