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Tektronix 454A User Manual

Tektronix 454A
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Gener al
L
O
W
-
VO
L
TAG
E P
O
WER
S
UPPL
Y
Ci r cui t
Descr i pt i on- 454zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
/
R
454A
The cu
r r ent
t
h
r oug
h
t
h
e
Ser i es
R
egul at or
st age
i s
cont r ol l e
d
b
y
t
h
e
E
r r or
Am
p
l i f i er
t o p
r ovi
d
e
t
he cor r ect
r egul at ed
out
p ut vol t age
.
T
h
e
L
ow-
V
ol t age
P
ower
Su
pp
l y
ci r cui t
p
r ovi
d es
t
h
e
o
p
er at i ng
p
ower
f or
t
h
i s
i nst r ument
f r om
t
h
r ee
r egul at ed
su
pp
l i es
an d
one
unr egul at e
d
s
u
pp
l y
.
E
l ect r oni c
r egul at i on
T
h
e
E
r r or
Am
p
l i f i er
i s
connect e
d
as
±
com
p ar at or
.
i s
use
d
t o
p
r ovi
d e
st abl e,
l ow- r i ppl e
out
p
u
t
vol t ages
.
E
ac h
R
ef er ence
vol t age
f or
t
he
com
p
ar at or
i s
pr ovi de d b
y
zener
r egul at e
d
su
pp
l y
cont ai ns
± sh
or t -
p r ot ect i on
ci r c
u
i t
t o
p
r e-
d
i o
d e
VR
1116,
w
h
i c
h
set s
t
he b
ase
of
Q1116
at
abo
u
t - 9
vent
i nst r
u
ment
d
amage
i f
±
su
pp
l y
i s
i nadver t ent l y
s
h
or t e
d
vol t s
.
T
he base
l evel
of
Q1124
i s
d
et er mi ned
by
vol t age
t o
gr oun
d
.
T
h
e
P
ower
I n
p ut
st age
i ncl
ud
es
t h e
V
ol t age
d
i vi
d
er
111123- 131124- 131125
b
et ween
t
h
e
o
u t p u
t
of
t
h
i s
Sel ect or
Assembl y
.
T
h
i s
assembl y
al l ows
sel ect i on
of
t h e
su
pp
l y
and
gr ound
.
R
1124
i s
ad
j
ust abl e t o
set
t
he
out
p ut
nomi nal
o p
er at i ng
vol t age an d
r egul at i ng
r ange
f or
t h e
vol t age of
t
h
i s s
up pl y t o
- 12
vol t s
.
R
1120
i s
t
he
emi t t er
i nst r
u
ment
.
F
i g
.
3- 17
s
h
ows
±
det ai l ed
b
l oc
k d
i agr am
of
t h e
r esi st or
f or
b
ot
h
com
p
ar at or
t r ansi st or s,
an
d
t
h
e
cu
r r ent
P
ower
Su
pp
l y
ci r cui t
.
sc
h
emat i c
of
t
h
i s
ci r cui t
i s
s
h
own
t
hr ou
g
h
i t
d
i vi
d
es
bet ween
01116
an
d
Q1124
.
T
he
out
p ut
on
di agr am
13
at
t h e
bac
k of
t
h
i s
manual
.
cur r ent
of
t
he Er r or
Am
p
l i f i er
st age
cont r ol s
t
h
e
con
d u
c-
t i on of
t
he
Ser i es
R
eg
u
l at or
st age
( t
hr o
u g
h
Q1133)
.
T
h
i s
o
u
t
p u
t
cur r ent
i s
ch
ange
d
t o p
r ovi
d
e
±
const ant ,
l ow- r i ppl e
- 12- vol t
o u
t
p ut
l eve
l
.
T
h
i s
occur s
as
f ol l ows
:
T
h
e
com
p
ar a-
P
ower
I n
p
ut
f
or act i on of
01116
an d
Q1124
at t em
p
t s
t o
mai nt ai n
e
q
ual
P
ower
i s
a
pp
l i e
d t o
t
h
e
p
r i mar y
of
t r ansf or mer
¤
1101
vol t ages
at
t h e
bases of
b
ot h
t r ansi st or s
.
I f t
h
e
- 12
V
ol t s
t
h
r oug
h
t
he 115- vol t
l i ne
f use
F
1101,
P
O
WER
swi t ch
adj
u
st ment ,
R
1124,
i s
t ur ne
d
cl oc k
wi se,
t
he cu
r r ent
S1101,
t
h
er mal
cut o
u
t
¤š
1101,
V
ol t age
Sel ect or
swi t c
h
t hr o
ug h
01124
i ncr eases
( 01124
base t en d
s
t o
9
¿
mor e
S1102
an
d
R
ange
Sel ect or
swi t c
h
S1103
.
V
ol t age
Sel ect or
p
osi t i ve
t
h
an
t
he
b
ase of
01116) ,
and
t
he
c
u
r r ent
t
h
r oug
h
swi t c h
S1102
connect s
t
h
e
spl i t
pr i mar i es of
T1
101
i n
p
ar -
01116
decr eases
.
Decr ease
d c u
r r ent
t h
r o
ug h
` Q1116
p
r o-
al l el
f or 115- vol t
nomi nal
o p
er at i on,
or
i n
ser i es
f or
d
uces
l ess
vol t age
d
r o
p acr oss
R
1118,
and
t h e
base
of
230- vol t
nomi nal
o p
er at i on
.
secon
d
l i ne
f
u
se,
F
1102,
i s
Q1133
goes p
osi t i ve
.
T
he emi t t er of
01133
pu
l l s
t
he base
connect e
d
i nt o
t
h
e
ci r c
u
i t
w
h
en
t he
V
ol t age
Sel ect or swi t c h
of
01137
p
osi t i ve
t o
i ncr ease
t
he
c
u
r r ent
t
hr o
u
gh
t
he
l oa
d
,
i s
set
t o
t
h
e
230
V
p
osi t i on
t o p
r ovi
d
e t
h
e
cor r ect p
r o-
t her eby
i ncr easi ng
t
he o u
t
p u
t
vol t age of
t h e
su
pp
l y
.
T
h
i s
t ect i on
f or
230-
V
oper at i on
( F
1102
c u
r r ent
r at i ng
i s
one-
p
l aces
mor e
vol t age
acr oss
d
i vi
d
er
R1123- R11124- 131125
h
al f
of
F
1101)
.
a
n
d
t
he d
i vi
d
er
act i on r et ur ns
t
he
base
of
01124
t o
about
- 9
vol t s
.
si mi l ar ,
b u
t
o
pp
osi t e,
act i on
t a
kes
pl ace
w
h
en
R
1124
i s
t
u r ned
count er cl oc
k
wi se
so
t
he base of
01124
i s
T
he
R
ange
Sel ect or swi t c h
,
S1103,
al l ows
t
h
e
i nst r
u
-
mor e
negat i ve
t
h
an
t
h
e
base of
Q1116
.
T
h e
- 12
V
ol t s
a
d
-
ment
t o
r eg
u
l at e
cor r ect l y
on
h
i g
h
er
or
l ower
t h
an
nor mal
,
j
u
st ment ,
R
1124,
i s
set
t o
p
r ovi
de
±
- 12- vol t
l evel
at
t
he
l i ne
vol t ages
.
E
ac
h h
al f
of
t
h
e
p
r i mar y
has
t a
p
s a
b
ove
an d
ou
t
p u
t
of
t
h
i s
su
pp
l y
.
bel ow
t
he 115- vol t ( 230)
nomi nal
p
oi
n
t
.
As
t
he
R
ange
Sel ect or
swi t c h
,
S1103,
i s
swi t ched
f r om
L
O
t o
œ
t o
,
mor e
t
u
r ns
-
ar e
ef f ect i vel y
a
dd
ed t o
t
he
pr i mar y
wi n
d
i ng
T
he
out
put vol t age
i s
r eg
u
l at e
d
t o
p
r ovi
d
e
±
const ant
an d
t
h
e
t ur ns
r at i o
i s
decr ease d
.
T
h
i s
mai nt ai ns
±
near l y
vol t age t o
t h e
l oa
d b y
f ee
d
i ng
±
sam
p
l e
of
t
h
e
out
pu
t
bac k
const ant
vol t age
i n t
he
secondar y
of
¤
1101,
eve
n
t
h
r oug
h
t o
t
h
e
Ser i es
R
egul at or ,
Q1137
.
F
or
exampl e,
ass
u
me
t
h
at
t he p
r i mar y
vol t age
h
as
i ncr ease
d
.
t
h
e
o
u t
p u
t
vol t age
i ncr eases
( mor e
negat i ve)
beca
u
se
of ±
c h
ange
i n
l oa
d
or an
i ncr ease
i n
l i ne
vol t age
.
T
h
i s
negat i ve-
goi ng
l evel
at
t
he
o
u
t
put
i s
ap
p
l i ed
acr oss
t
he vol t age
T
h
er mal
cut out
¤š
1101
p
r ovi
d
es
t
h
er mal
pr ot ect i on
f or
d
i vi
d
er
R
1123-
R
1124-
R
1125
and
t
he base of
01124
goes
t h
i s
i nst r ument
.
I f t
he
i nt er nal
t emper at
u
r e
of
t
h
e
i nst r u-
negat i ve
al so
.
T
h
i s
r educes
t h
e c u
r r ent
f l ow
t
h
r o
ugh
Q1124,
ment
excee
d
s ±
saf e
o
p
er at i ng
l evel ,
¤š
1101
opens
t o
whi ch
al l ows
Q1116
t o
conduct
mor e
an d
i t s
col l ect or
goes
i nt er r u
p
t
t
he
a
pp
l i e
d p
ower
.
Wh
en
t h e
t em
p er at ur e
r et ur ns
negat i ve
.
Wh
en
t
h
e
col l ect or
of
01116
goes
n
egat i ve,
t
he
t o ±
saf e
l evel ,
¤š
1101
a
u
t omat i cal l y
cl oses
t o
r e- a
pp
l y
t h
e
b
i as
on
01133
i s
r e
d uced,
r es
u
l t i ng
i n r e
d
u ced c u
r r ent
p
ower
.
t
h
r oug
h
t
he
Ser i es
R
eg u
l at or ,
01137
.
R
e
d
u
ce
d
c
u
r r ent
t
hr ou
g
h
01137
al so
means
t
h
at
t h
er e
i s
l ess
cu
r r ent
t
hr ough
t
h
e
l oa
d
an
d
t
h
e
out
put vol t age
d
ecr eases
( l ess
negat i ve)
.
·
- 12
V
ol t
Suppl y
±
si mi l ar
manner ,
t h
e
Ser i es
R
egu
l at or
an d
E
r r or
Am
p
l i f i er
st ages
com
p ensat e
f or
out
p ut c
h a
nges
d
ue
t o
r i
pp
l e
.
T
he
- 12-
V
ol t
Su
pp
l y
pr ovi des
t
he r ef er ence vol t age
f or
t h
e
r emai ni ng
s
u
pp
l i es
.
T
he
o
u
t
p ut
f r om
t
h
e
secon
d
ar y of
¤
1101
i s
r ect i f i e
d
by b
r i
d
ge
r ect i f i er
CR1112A- D
.
T
h
i s
vol t age
i s
f i l t er e
d
by
C1112- 131112
an
d
t
hen ap
p
l i e
d t o
t
he
T
he
S
h
or t -
P
r ot ect i on
Am
p
l i f i er
st age,
Q1119,
p
r ot ect s
- 12-
V
ol t
Ser i es
R
eg u
l at or
st age
t o p
r ovi
d
e
±
st abl e
out
put
t
h
e
- 12-
V
ol t
Su
pp
l y
i f
t
h
e
o
u
t
p ut
i s
s
h
or t ed
.
F
or
nor mal
vol t age
.
T
he
Ser i es
R
eg u
l at or
can
be
com
p
ar e
d
t o
±
var i a
b
l e
o
p
er at i on
t
h
e
emi t t er - base
vol t age of
01119
i s
not
e
n
oug
h
r esi st ance
w
h
i c h
i s
c
h
ange
d
t o cont r ol
t
he ou
t
p u
t c
u
r r ent
.
t o
bi as
i t
on
.
H
owever ,
w
hen
t
he
out
p
u t
i s
s
hor t ed
,
h
i g h
3-
3
1

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Tektronix 454A Specifications

General IconGeneral
BrandTektronix
Model454A
CategoryTest Equipment
LanguageEnglish

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