Tektronix 576 - Page 25

82 . Tu
r n
t h
e
V A R IA BLE CO LLE CTO RS UPPL
Y
con-
trol cloc k wise a nd note t he d isplay of emitter lea kage cur-
r
e
n t with t h e base te r minal open .
83 . Set t h e Te r minal Selector switc h to S H O R T a nd
note t h e d is p lay of emitter lea kage current wit h t he base
terminal sh o r te d to g r oun d .
84 . Set t he following Ty pe 576 co
n
trols to :
VER TICA L 5 mA
A MPL IT U D E

5 mA
Te r minal Selector

EM ITT ER T ERM ST
EP
G EN
ST EP F AM I L Y

ON
Turn t he V A R IA BLE CO LLE CTO R S UPPL Y control
cloc k wise and n ote t h e d is p lay of collector cu r re n t vs .
collecto r -emitter voltage with current ste p s a pp lied to t he
emitter of t he transistor (see F ig . 2-1 9B) .
85 . Set t h e following Ty pe 576 controls to :
ST EP F A M I LY

O FF
Termi n al Selector

EM ITT ER T ERM OPEN
(O R ΕΧΤ )
R econnect t he p atc h cor d between the ST EP G EN OU T-
PU T connector
a
nd t he ΕΧΤ B AS E O R EMIT INPUT con-
nector .
86 . Set t
he
ST
EP F
A
M
Ι L
Y
butto
n
to ON a
n
d
note
α
d is p lay simila r to t
h
at
see
n i n ste
p
84
.
T h is completes t h
e
first-time operation .
G ENER A
L
O
PER ATI NG I NF O RM ATIO N
C R T
T h eCR T in t h e Ty pe 576 h as α p
e
r manently etc h
e
d
inter n al g r aticule . T he g r aticule is 10 d ivisions by 12 d ivi-
sions, each d ivision being 1 cm . Ill u mination of t h e g r ati-
cule is co n t r olle d by t he G R ATIC ULE 1 LLUM control . Pr o-
tective s h iel d s for t h e CR T and t he fibe r -o p tic rea d out d is-
p lay are fitted to t h e bezel . T he bezel cove r s t he C R T an d
t he fiber-o p tic rea dout d is p lay . To r emove, loose n t he se-
cu r ing screw an d pull ou t on t he b ottom of t he b ezel .
Α blue filte r h as been provide d to im p rove t he contrast
of t h e d is p lay w hen t he ambient lig h t is inte n se . T h is filter
may be installe d (or remove d ) by r emoving t he bezel and
sli d ing t h
e
filter
from between t he CR T p r otective sh iel d
and t he bezel frame .
R ea d out
T h e rea d out locate d to t he rig h t of t h e CR T is ma d e up
of t he fiber-optic d is p lays and t h eir titles_ T h
e
fi b
er-optic
d is p lays s
h
ow numbers and un its
(5
mA,
2 V, etc .) t h e
Operating Instructions-- Type 576
values of w h ic h are α f u nction of front- p anel control set-
tings . T he titles a r e wo r d s printed on t h e fiber-o p tic d is p lay
s h iel d attac h e d to t he bezel . T h ese wor d s in d icate t h e ch ar-
acteristics of t he C R T dis p lay to w h ic h eac h fiber-o p tic
d is p lay is relate d (PER VER T DI
V , PER
ST
EP ,
etc .) . Illu-
mination of t h e titles and t h
e
fibe r -o p tic d i
p
lays is con-
trolle d by t
he RE
ADO U T I LLU M control
.
It
s
h o
u
l d be
note d t h at as t he illumination of t he rea dout is re d uced, t h e
fiber-optic d isplay of β or g m p er d ivision tu r ns off before
t he ot he r fiber-o p tic d is p lays .
Intensity
T
he intensity
of
t he d
is p lay on
t he
CR
T
is cont r
olle
d by
t
h e
I NT
EN
SITY
control . T h
is control s
h
oul d be ad ju ste d so
t h at t he dis p lay is easily visible but n
ot
ove
r
ly
b r ig h t . It will
p r obably r e q uire rea d j ustment for d ifferent d is p
lays
. P artic-
ula r care s h oul d be exe r cise
d
w hen α s p ot is
being d
is-
p layed . Α h ig h intensity spot may burn t
he
C R
T ph
os
ph
or
causi ng p e r ma nen t d amage to t he CR T .
F
ocus
T he focus of t h
e
CR T d is p lay is controlle d by t he F O-
CUS control . T h is control sh o u ld be ad j uste d for o ptimu m
d is p lay d
efi
n ition .
Positioning
T h e p osition of t he d is p lay on t h eCR T g r
aticule, bot
h
vertically and h orizontally, is cont r olled by
four sets of
controls : t he vertical and h orizo n tal P OSITIO N controls,
t he P
O L A R ITY switc
h ,
t h
e
DIS PL AY O FF SET con trols
a
n
d t he DIS PL AY I NVER T,
Z
ER O and CA L butto n s .
T he p osition controls p rovide coarse and
fine p
ositio
n i ng
of t he d is p lay bot
h vertically
and
h
orizo n
tally . E
ac
h
coarse
P
OSITIO N switc
h p
r ovi d es 5- d ivision
incremen
ts of
dis p
lay
p ositioni n g .
E
ac
h F
I
NE P
OSITIO
N control h
as
α contin-
uous range of g r eater t h an 5 d ivisions . T he position cont r ols
sh oul d not be used to p osition t he zero r eference off t he
CR T .
T
h e DIS PL AY O FF SET controls
may
be used fo F t h is
pur p ose . If t h
e
d isplay is magnifie d eit
h
er
vertically
or
h or-
izontally u sing t he DIS PL AY O
FF
S
E
T Selector
switc h , t he
r anges of t h e p osition controls are inc r ease d 10 times .
T he P O L A R ITY switc h p ositions t h e zero signal p oint of
α d is p lay (located by p ressi ng t h e Z ER O button) to α p osi-
tion convenient for ma k i ng measureme n ts on an ΝΡΝ de-
vice, α
ΡΝΡ d evice or w hen ma k ing an AC
measu r ement .
T he DIS PL AY O FF SE T controls p r ovi d e calibrate d off-
set (or p ositioning) of t h e d is p lay eit h er ve r tically o r h ori-
zontally . T h ese controls may be use d eit he r to ma k e α
measurement or to p osition p artic u lar p ortions of α d isplay,
w h ic h h as
been
magnifie d , on t h
e
CRT g r aticule . T he DIS-
PL AY O FF S ET Selector switc h
d
etermi
n es w h et h er th
e
dis-
play will be offset vertically or h orizontally an
d
t h e
CEN-
TERLINE V A
LUE
switc h p rovi d es t h
e
offset . Und er un-
magnified con
d itions, 10
divisions of offset are available
.
Wh en t he DIS PL AY O FF SE T Selector switc h is set
to o
ne
of its M AG N I F I ER positions, 100 d ivisio ns of offset are
available .
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