Tektronix 576 - Page 20

O p e r ating Inst r uctions-Ty p e 576
40 . R emove t he dio d e f r om t h
e
dio d e a d ap te r and re-
p
lace it wit h α
8
volt Zener dio de . Align t he d io de so t h at
its cat h o d e is connecte d to t he emitter termi n al .
41 . Set t he LEF T-O FF-R IG HT switc h to RIG H T and
turn t he V A R IA BLE CO LLE CTO R S UPPL Y control cloc k -
wise . N ote t h at t he d is p
lay
s h ows bot h t he forwa r d and
r everse c h aracteristics of t he Zener diode (see F ig . 2-10) .
F ig . 2-10 . Di s pl ay o f Z ene τ d i ode Ι vs . V c h aracterist i c wit h PO-
LARITY switch
set to
AC .
Dis p lay Offset an d M agnifier
Note t he d is p lay of t he reve r se voltage cha r acteristic of
t he
Ze
n er d io d
e .
43 . Position t he dis p lay to t he center of t h e CR T grati-
c ule wit h t h eve r tical P OSITIO N switc h (see Fig . 2-1 1 Α ) .
44
. Set t he DIS PL AY O FF SET Selector switc h to
H
O
R IZ Χ 10 . P ress t he Z ER O button an d , using
t h e h ori-
zontal
F I NE P OSITIO N cont r ol, a d ju st the sp otso th at it is
on
t
h
e center ve r tical line of t he CR T gratic u le . T h is s p ot
p
osition re p resents the zero offset p ositio n . R elease the
Z
ER O
button a nd set th e DIS PL AY O FF S E T Selector
switc h to
H O R IZ Χ 1 .
45 . Turn t h e C EN T ERL I NE V A LUE switc h from t he 0
position cloc k wise, until t h e Zener brea kd own p ortion of
th
e
d isplay is wit h in ±0 .5 divisions of t h e center ve r tical
li n
e (see F
ig . 2-11 Β ) . N ote t h e nu mberon t h
e
C EN T ER-
L I NE VA LUE switc h w h ic h a pp ears in t he blue win d ow
below t he wor d DI V . T h is numbe r m u lti p lied by t he PER
HOR IZ DI V r ea d o u t value gives t he
app
roximate
val
ue
of
t he
brea
k d own
voltage of t h is
Zener
d io d
e . F
or t
he
d io d
e in
t h e exam p le s h own in F ig . 2-11, t h e a pp r oximate Ze n e r
brea k down voltage is 4 d ivisions times 2 V / d ivision = 8
volts .
46 . Set t he DIS PL AY O FF SE T Selecto r switc h to
2-12
H O R IZ Χ 10 . N ote t h at PER H O R IZ DI V rea d ou tvalue h as
ch
a
nged to in d icate t h e 10 times multi p lication . By expan d -
ing t he scale, α meas u
rement can
be made
of
t
h
at
pa rt of
t he c h aracteristic w h ic h was not quite
offset
to
t he center
vertical line of t he CR T g r aticule (see F ig . 2-11C) . T
h is
value w hen a dd ed to t h e a pproximate value (or subratcte d
:(
Α
)
NONE
ENNEE
ι
ι
Ι
Ι (C)
ι
Ι
ι
1
Ι
Ι
F--
Ι
ι
Ι
Ε
m A
D Ιν
ΡΕ
ο
R
ι
.
Ε
Ρ
Τ
DIV
Ρ ΕΛ
Η
R
Ο
[~
2π0
Ζ Ιη ν
DIV
ΡΕ R
5ο
Ε
Ρ

» Α
β
PE R
DIV
5
2
ν
ε
MA
Ιι 00 ιε
F ig . 2-11 . Di s p lays o f m eas ur e m ent o f Z ene τ b r ea k down voltage
u s in g t h e DIS
PLA Y
O
FF
S
ET
Selector
a n
d C ENTE R LINE
VALUE
sw
i
tc
h
es, ( Α
)
D IS
PLA Y
O
FF S ET
Selector sw i tc
h
set to ΗΟ
R ΙΖ Χ
1
and C ENTE R L I NE V A LU
E
sw i tc h set to 0 ; ( Β ) CE N TE R LINE
V ALUE sw i tc h set to
4
; (C) DI S PLA
Y
O FF S ET Se
l
ector switc
h
set
to ΗΟ R ΙΖ Χ 10 .
Ζ
if t h e a pp roximate value was greater
t h
an
t h e actual value)
p ro d uces α
more exact measurement of t he brea kd own volt-
age . In t he exam p le sh own in F ig . 2-11, 400 m V s h ould be
one, B r ea kd ow n
V _oltag_e
JIM 0
loom
OMENS
ι .
ιι
r ι ~~ ιιιι
Ε
ΡΕΛ
Τ
D IV
WI Α
ι
__
1
ι
Η
Ο
R
PER
Η
Ο
R
2
ο
IV
PER
DIV
1
Ι Τ
10
PER
Τ
1
Ι
ι
ιιιιι
~~ ιιιι
Ρ Α Ε »
ΕΡ
» Α
9m
PER
DIV
Ιιτι 0 Κ
PE R Ι 0 Ο Κ
DIV
rv V R
1(
Β
)
Ε
DIV
Τ
» Α
1
PER
Η
42 . Set th
e
following Type 576
cont r ols to :
ι
Τ 50
Ι
» Α
H
O
R IZO N TA L
2 V CO
LLE
CTO
R
Ι
β
oR
POLARITY
-( ΡΝΡ )
PER
PER
DIV
It l t0k