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Tektronix 454A User Manual

Tektronix 454A
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Ci r cui t
Descr i p
t i on- 454zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
‘
/
R
454A
an
d
t
h
e
‘
Tr i gger
L
evel
Cent er
a
d
j
ust ment
R
643
.
T
h
e
‘
Tr i gger
L
evel
Cent er
set s
t
h
e
l evel
at
t
h
e
b
ase of
Ÿ
646
so
t he di spl ay
i s
cor r ect l y
t r i gger e
d
w
h
en
t
h
e
‘
LEVEL
con-
t r ol
i s
cent er e
d
.
T
h
e
‘
LEVEL
cont r ol
var i es
t
h
e
b
ase
l evel
of
Q646
t o
sel ect
t
h
e poi nt
on
t
h
e
t r i gger
si gnal
w
h
er e
t r i gger i ng
occ
u
r s
.
T
h
e
sl o
p e of
t
h
e
i n
p ut
si gnal
w
h
i c
h
t r i gger s
t
h
e
‘
swee
p
Di odes
C
R
636-
VR
641
an d
C
R
638-
VR
642
l i mi t
t
h
e
i s
d
et er mi ned
b y
t
h
e
‘
S
L
O
PE
swi t c h
,
S650
.
Wh
en
t
h
e
‘
t r i gger
si gnal
c
h
ange
at
t
h
e base
of
0636
t o
a
b
out
t wo
vol t s
S
L
O
PE
swi t c
h
i s
set
t o
t
h
e
-
posi t i on,
t
h
e
col l ect or
of
mor e
p
osi t i ve
an
d
negat i ve
t
h
an
t
h
e
l evel
at
t
h
e
base
of
Q636
i s
connect e
d t o
t
h
e
+12- vol t
su
pp
l y t
h
r oug
h
C
R
651,
Q646
.
F
or
exam
p
l e,
as
t
h
e
base
of
Ÿ
646
r i ses
p
osi t i ve
w
h en
R
651
an d
R
658
.
T
h
e
ano
d
e
of
C
R
652
i s
gr o
u
n d ed
t
h
r o
u
g
h
t
h
e
‘
LEVEL
co
n
t r ol
i s
t
u
r ne d cl oc
k
wi se,
t
h
e vol t age
at
R
652,
an d
t
h
i s
d
i o
d e
i s
r ever se
bi ase
d
.
Now
t
h
e
col l ect or
t
h
e
cat
h
ode
of
zener
d i ode
VR
641
r i ses
p
osi t i ve
al ong
wi t
h
c u
r r ent
of
0646
must
f l ow
t
h
r oug
h
CR
655,
R
656,
L
656,
t
h
e
c
h
ange
at
t
h
e base of
Ÿ
646,
but
i t
r emai ns
t
h
r ee
vol t s
t
h
e
p
ar al l el ,
com
b
i nat i on
of
C
R
657
an d
R
666-
L
664,
R
659
mor e
p
osi t i ve
.
T
h
er ef or e,
w
h
en
t
h
e
t r i gger
si gnal
l evel
at
t
h
e
an
d
R
658
t o
t
h
e
+12- vol t
su
p
p
l y
( see
F
i g
.
3- 11)
.
Si nce
t
he
b
ase
of
Q636
r i ses
mor e
t
h
an
about
3
. 5
vol t s
mor e p
osi t i ve
out
p
ut p
ul se
f r om
t
h
e
‘
Tr i gger
Gener at or
ci r c
u
i t i s
der i ve
d
t
h
an
t
h
e base of
0646,
C
R
636
i s
f or war
d
b
i ase
d t o
l i mi t
f r om
t
h
e
negat i ve- goi ng
p or t i on of
t
h
e
si gnal
a
pp
l i e
d
t o
t
h
e
t
h
e
si gnal
excur si on
.
T
h
e act i on
i s
si mi l ar
f or
C
R
638-
Tr i gger
TD
st age,
t
h
e
swee
p
i s
t r i gger e
d
on
t
h
e
negat i ve-
VR
642
on
negat i ve- goi ng
si gnal s
.
T
h
i s
conf i gur at i on
p
r o-
goi ng
sl o
p e
of
t
h
e
i n
p ut
t r i gger
si gnal
( si gnal
a
pp
l i e
d t o
vi
d
es
pr ot ect i on
f or
t
h
e Sl o
p
e
Co
mp
ar at or
st age
f r om
Tr i gger
TD
st age
i s
i n
ph
ase
wi t
h
t
h
e
i n
p
ut
si gnal
f or
-
h
i g
h
- am
p
l i t u
d
e
t r i gger si gnal s
.
sl o
p
e
t r i gger i ng)
.
Wh
en
t
h
e
‘
SL
O
PE
swi t c
h
i s
set
t o
+,
con
d
i t i ons
ar e
r ever se
d
( see
F
i g
.
3- 12)
.
Q646
i s
connect e
d
t o
t
h
e
+12- vol t
s
up
pl y
t
h
r oug
h
C
R
652,
R
652
an
d
R
658
.
R
637
est abl i s
h
es
t
h
e emi t t er
cur r ent
of
Q636
an
d
Q646
.
T
h
e
ano
d e of
C
R
651
i s
gr oun
d ed
t
h
r oug
h
R
651
t o
d
i ver t
T
h
e
t r ansi st or
wi t
h
t
h
e
most
posi t i ve
base cont r ol s
con
d
u
c-
t
h
e
col l ect or
cur r ent
of
Q636
t
h
r o
u
g
h
t
h
e Tr i gger
TD
st age
.
t i on
of
t
h
e
com
p ar at or
.
F
or
exam
p
l e,
assume
t
h
at
t
he
T
h
e
si gnal
a
pp
l i ed
t o
t
h
e Tr i gger
TD
st age
i s
now
180
°
o
u
t
t r i gger
si gnal at
t
h
e
emi t t er
of
Q624
i s
posi t i ve- goi ng
an
d
of
ph
ase
wi t
h
t
h
e i n
p ut
t r i gger
si gnal ,
an d
t
h
e
swee
p
i s
0636
i s
f or war
d
bi ase
d
.
T
h
e
i ncr ease
d
cur r ent
t
h
r o
u
g
h
t r i gger ed
on
t
h
e
p
osi t i ve- goi ng
p
or t i on
of
t
h
e
i n
p
u
t
si gnal
.
R
637
pr o
d
uces ±
l ar ger
vol t age dr o
p
,
and
t
h
e
emi t t er s
of
bot
h
0636
and
Q646
go
mor e
posi t i ve
.
‘
mor e
p
osi t i ve
vol t age
at
t
h
e
emi t t er
of
Q646
r ever se
b
i ases
t
h
i s
t r ansi st or ,
si nce
i t s
base
i s
h
el
d
at
t
h
e
vol t age
set
by
t
h
e
‘
LEVEL
Tr i gger
TD
cont r ol ,
an
d
i t s
col l ect or
cur r ent d
ecr eases
.
At
t
he
same
The
Tr i gger
TD
st age
s
h
a p
es
t
h
e o
u
t
p
u
t
of
t
h
e
Sl o
pe
t i me,
Q636
i s
f or war
d
b
i ase
d
an
d
i t s
col l ect or
cur r ent
i n-
Â
ompar at or
t o
p
r ovi de
±
t r i gger
p
ul se
wi t
h ±
f ast
l ea
d
i ng
cr eases
.
(
N
ot e
:
T
h
er e
i s
±
nar r ow
r egi on
at
t
h
e
swi t c
h
- over
e d
ge
.
Tunnel
d
i o
d e
C
R
657
i s
q
ui escent l y
bi ase
d so
i t
p
oi nt
w
h
er e
b
ot
h
t r ansi st or s
con
d uct
as
±
l i near
am
p
l i f i er )
.
oper at es
i n
i t s
l ow- vol t age
st at e
.
T
h
e
cur r ent
f r om
one
of
N
ot i ce
t
h
at
t
h
e
si gnal
c
u
r r ent s
at
t
h
e
col l ect or s
of
Q636
t he
t r ansi st or s
i n t
h
e
Sl o
p e
Com
p
ar at or st age
i s
d
i ver t e
d
an
d
Q646
ar e
o
pp
osi t e
i n
p
h
ase
.
T
h
e
swee
p
can
b e
t r i gger e
d
t hr o
u
g
h
t
h
e
Tr i gger
TD
st age
by
t
h
e
‘
S
L
O
PE
swi t c h
.
As
f r om
ei t
h
er
t
h
e
negat i ve- goi ng
or p
osi t i ve- goi ng
sl o
p
e
of
t
h
e
t hi s
cur r ent
i ncr eases
d
u
e t o
± c
h
ange
i n t
h
e
t r i gger
si gnal ,
i n
p ut
t r i gger
si gnal
by
p
r oduci ng
t
h
e
t r i gger
p
u
l se
f r om
t
u
nnel
d
i ode
C
R
657
swi t c h
es
t o
i t s
h
i g
h
- vol t age
st at e
.
L
664
ei t
h
er
t
h
e
si gnal
at
t
h
e
col l ect or
of
Q646
f or
-
sl o
pe
opposes
t
h
i s
s
u
dd
en
c
h
ange
i n
cur r ent ,
w
h
i c
h al l ows
mor e
o
p
er at i on,
or
t
h
e
si gnal at
t
h
e
col l ect or
of
Q636
f or
+
sl o
pe
cur r ent
t o p
ass
t
h
r ou
g
h
CR
657 and
swi t c
h
i t
mor e
qu
i c
k
l y
.
o
per at i on
.
T
h
i s
sel ect i on
i s
ma
d e
by
t
h
e
‘
S L
O
PE
swi t c
h
,
A
s
t
h
e
c
u
r r ent
f l ow
st a
b
i l i zes,
L
664
agai n
con
d
u
ct s
t
he
S650
.
ma
j
or p
ar t
of
t
h
e
c
u
r r ent
.
H
owever ,
t
h
e cur r ent
t
h r o
u
g
h
CR
657
r emai ns
h
i g
h
enoug
h
t o h
ol d
i t
i n
i t s
h
i g
h
- vol t age
st at e
.
T
h
e
ci r cui t
r emai
n
s
i n t
h
i s
con
d
i t i on unt i l
t
h
e cur r ent
Wh
en
t
h
e
‘
LEVEL
cont r ol
i s
set
t o 0 ( mi d
r ange) ,
t
he
f r om
t
h
e
Sl o pe
Com
p ar at or
st age
d
ecr eases
due
t o
±
c
h
ange
base of
Q646
i s
at
about
- 0
. 25
vol t
.
T
h
e
b
ase- emi t t er
d r op
i n
t
h
e
t r i gger
si gnal
a
p
pl i e
d
t o
t
h
e
i n
p
u
t
.
T
h
en,
t
h
e
c
u
r r
ent
of
Ÿ
646
set s
t
h
e
common
emi t t er
l evel
of
Q636- Q646
t o
t
h
r o
u
g
h
CR
657
d
ecr eases
an d
i t
r ever t s
t o
i t s
l ow- vol t age
about
one
vol t
negat i ve
.
Si nce
t
h
e
base of
Q636
must
be
a
b
out
0
. 65
vol t
mor e
p
osi t i ve
t
h
an
i t s
emi t t er bef or e
i t
can
st at e
.
con
d
uct ,
t
h
e
com
p
ar at or
swi t c
h
es
ar oun
d
t
h
e
zer o- vol t
l evel
of
t
h
e
t r i gger
si gnal
( zer o- vol t
l evel
on
t
h
e
t r i gger
si gnal
cor r esp
on
d
s
t o
a
b
out
- 0
. 25
vol t
at
t
h
i s
poi nt ,
wi t
h
cor r ect
p
ul se
Ampl i f i er
cal i br at i on)
.
As
t
h
e
‘
LEVEL
cont r ol
i s
t
u
r ne
d
cl oc
k
wi se
t owar d
+,
t
h
e
vol t age
at
t
h
e
base of
Q646
becomes
mor e
T
h
e
t r i gger
si gnal
f r om
t
h
e
Tr i gger
TD
st age
i s
connect e
d
p
osi t i ve
.
T
h
i s
i
n
cr eases
t
h
e cur r ent
f l ow
t
h
r o
u
g
h
R
637
t o
t o
t
h
e
base
of
t
h
e
Pu
l se
Am
p
l i f i er ,
Q664,
t
h
r oug
h
R
666,
p r od
u
ce
±
mor e
posi t i ve
vol t age
on
t
h
e
emi t t er s of
bot
h
C666,
an d
one
h
al f
of
L
664
.
T
h
e
t r i gger
pu
l se
at
t
h
i s
poi nt
0636
an d
0646
.
Now
t
h
e
t r i gger
si gnal
must
r i se
mor e
i s
basi cal l y
±
nar r ow,
negat i ve- goi ng p
u
l se
wi t
h
±
f ast
r i se
.
3- 1
6
p
osi t i ve
b ef or e
Q636
i s
b
i ase
d
on
.
T
h
e
r es
u
l t ant
C
R
T
di s-
pl ay
st ar t s at
±
mor e
p
osi t i ve
p oi nt
on
t
h
e
d
i s
p
l aye
d
si gnal
.
Wh
en
t
h
e
‘
LEVEL
cont r ol
i s
i n t
h
e
-
r egi on,
t
h
e
ef f ect
i s
t
h
e
opposi t e
t o p r o
d
u
ce ±
r esul t ant
C
R
T
d
i s
p
l ay
w
h
i c
h
st ar t s at
±
mor e
negat i ve poi nt
on
t
h
e
t r i gger
si gnal
.

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Tektronix 454A Specifications

General IconGeneral
BrandTektronix
Model454A
CategoryTest Equipment
LanguageEnglish

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