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1. Part of Made in India,
Design Innovation
Workshop,2015
A
Fresh
New
Experience
in
Project-­‐Making
&
Learning!

2. PHYSICSINVESTIGATORY
PROJECTON
TRANSISTORAS
AMPLIFIER&SWITCH

3. Do
you
know
that
there
are
billions
of
transistors
used
in
the
produc6on
of
ICs
and
microprocessors?
Transistors
are
not
only
used
for
amplifica6on
in
sound
systems
but
their
ability
to
switch
between
the
two
states
(ON/OFF)
makes
them
the
nerve
cell
of
informa6on
technology.
In
this
project,
you
will
learn
about
the
characteris6cs
of
a
transistor
and
how
can
it
be
used
as
an
amplifier
and
a
switch.
In
this
project,
you
will
need
a
transistor,
two
resistors,
a
preset,
two
LEDs,
a
breadboard,
a
mul6meter
and
a
few
connec6ng
wires.
Varying
input
voltage
is
provided
to
the
base-­‐emiLer
junc6on
of
the
transistor
using
a
voltage
divider
circuit
made
using
a
preset.
The
cut-­‐off,
ac6ve
and
satura6on
regions
of
the
transistor
are
iden6fied
by
comparing
the
intensity
of
the
two
LEDs,
one
on
the
input
side
(base-­‐emiLer
junc6on)
and
the
other
on
the
output
side
(collector-­‐emiLer
junc6on).
In
the
cut-­‐off
region,
both
the
LEDs
are
OFF.
In
ac6ve
region,
the
LED
connected
to
the
collector-­‐emiLer
side
glows
brighter
than
the
LED
connected
to
the
base-­‐emiLer
side
and
on
rota6ng
the
preset,
the
intensity
of
the
former
LED
increases
more
than
the
laLer.
Now,
an
input
voltage
was
set
at
the
common
terminal
of
the
preset
and
it
was
measured
using
a
mul6meter.
The
base
and
the
collector
voltages
w.r.t
the
emiLer
were
measured
and
compared.
Similarly,
the
base
current
(Ib)
and
collector
current
(Ic)
were
measured
and
compared,
using
which
the
amplifica6on
factor
(hFE
=
Ic/Ib)
was
calculated.
The
experimental
value
of
hFE
lies
between
100
and
400
and
therefore,
it
verifies
that
the
transistor
is
in
ac6ve
region
and
acts
as
an
amplifier
with
the
base-­‐emiLer
junc6on
forward
biased
and
the
base-­‐collector
junc6on
reverse
biased.
When
the
preset
was
rotated
to
its
extreme
leU,
both
the
LEDs
glow
brightly
and
the
transistor
reaches
its
satura6on
stage.
The
amplifica6on
factor
was
calculated
as
above.
The
hFE
obtained
was
less
than
100.
In
this
case,
the
transistor
acts
as
a
switch.
Again
the
base
and
the
collector
voltages
were
measured
and
compared
to
verify
the
condi6on
of
the
satura6on
state.
Both
the
base-­‐emiLer
and
base-­‐collector
junc6ons
are
forward
biased
in
the
satura6on
state.
The
value
of
the
satura6on
voltage
for
the
transistor
was
found
to
be
0.25-­‐0.6
V.

4. Have
a
look
at
what
we
provide
in
our
Project
Kit!
CoolJunk
is
India's
fastest
growing
DIY
(do-­‐it-­‐yourself)
kits
company
focused
on
project-­‐based
learning
in
science,
engineering
and
technology.
Having
20,000
users
in
India,
US,
Singapore,
Middle
East
and
New
Zealand,
the
CoolJunk
kits
are
known
for
quality,
innovaUon
and
high
producUon
value.
CoolJunk
has
been
featured
in
naUonal
and
internaUonal
journals
including
Wallstreet,
Yourstory,
Hindu
Business
Line,
NextBigWhat
and
was
tagged
as
the
coolest
Indian
start-­‐up
in
IAN
Bootcamp-­‐2011.
You
may
also
refer
to
the
video:
Transistors
For
more
projects
visit
our
website:
CoolJunk
All
tools
and
components
in
one
box.
Step
by
step
visual
instrucUons
Detailed
experiment
theory
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us
on:
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