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Log Amp

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Log
Log -Amplitien
Loganthimic Ampiien
Basie Loq-Gena
is
Def- t
Pnoduces
electnonic
am
output
an
that
that
that
to
ponoPottiomol
is
app lied
the
thelooenithum
CinCuit
inpud
R
I
vi
The
tnansistor
Collectoos
a
and
base g9nounded
1ts
withn
is Connectad. m
a t Vintual
nelatimship
N-I
FF
qNoumd.
Centiqunotion
t n a n d diode
E
No
opAnp
oleined as
I s e VeEKT
the tramsdiode
Conbigunoation.
E
-
e
) qnounded base
and
hen
tansist
Ts
whese
Is
Vae/KT
emrtte
Satunatiom
is the Volt-tempejatuene
Curent amd 79.
Eauivalent
VBEKT +
Te L S
Since Te?Is
e
Is
APpying
natunal
l
both
on
Sides
mo
neaovangua
BE
KT In
Feern the fiqwne
amd VBE-V
Theefhe
whene
VR=RTs
w
MM
R
Nu
wiblompewsatiow of Emitto
tmp
Loqanitomic
tig)
Sotwnalwn unent
fig
P
Voi isoumd
ti, the output
the
om
Val -KT
and
the
R,Is
oudput Voz
Vo2=-T nT.
Subtractor
op-Amp
e
the
Coniquwned
A3 is
a
uill
ukzct*
a
tuo umhuts.
Vo-IKTn Y
Vo= KTI
whee
Jhe
amd
the
with
esistoy
ovenall
P
the
Kre
wTth
en
emoYed
been
Shclu Sion
Voltoqe
Soutce
e
Gntut n h
the
Gnat
is lontiquned fa
opAmp A
Senitive
has
tempesnatune
empesiotwre
he
Set
Extesinod
Single
a
the depen dence
hene-fte
deyice
VR>
with
the
effet of
o
cfet
tempe otne
a
poSitive temp Coefficient
Votoge
V
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