Tektronix 576 - Page 16

O p erati n g
Instructions-Ty p e576
V e r tical
Deflectio n
P lates
Horizontal
Deflectio n
P
lates
F ig . 2-5 . Bas i
c
Block
diagram
test .
sh owing ty p
ical
co n nect
i
ons o
f
Collector S upp ly, Ste p Generator and D is p lay Am p l i fiers to t he device un d e r
T
he
r esult is families of c h aracteristics curves traced on α
CR T .
T he Collector Sup p ly circuit normally p ro d uces α full-
wave r ectifie d sine wave w h ic h may be eit h er positive- or
negative going . T h e am p litu de of t he signal can be varie d
from 0 to 1500 volts as d etermine d by t he MAX PEAK
VO L TS switc h an d t he VA R IA BLE CO LLE CTO R S UPPL Y
control
. T h is Collector S u pp ly ou tp u t is ap plie d to t he col-
lecto r (or e q uivalent) terminal of t he
d
evice ιι nde
r test .
T he Ste p Generator prod u ces ascen d ing ste p s of current
or voltage at α normal rate of one ste p p er cycle of t h e
Collector Su pp ly . T h e amount of cu r r en t o r voltage p er
step is controlle d by t h e A MPL IT U D E switc h and t he total
number of ste
p s
is cont r olle d by t h
e
NUMBER O F ST EP S
switc
h . T h is Ste p Generator o
u
t p
u
t may be ap plie d to
eit h er t h
e
base or t he emitter (o r e q uivalent) terminals of
t he d evice unde r
test .
T he d is p lay am p lifiers a r econnecte d to t
he
d
evice
und er
test . T h
ese
am p lifiers meas
u
re t
h e effects of
t
he Collector
Su
pp ly
an d of
t h e Ste p Generator
on
t he d evice und er test,
am
p
lify t h
e measu
r
ements
and apply t h
e r
esulting voltages
to t h e d eflectio n p lates of t he CR T . T h
e
se n sitivities of
t h ese am p lifiers are con trolle d by t
he
VER TICA L C
UR-
REN T/DI V switc h and t h e H OR IZO N TA L VO L TS/DI
V
switc h .
Fig . 2-5 is α bloc k d iag r am s h owi n g t h
e
connection of
t h ese ci r cuits to t he device und er test for α ty p ical measure-
ment .
2- 8
F I R ST TIME O PER ATIO N
Wh en t he Ty pe 576 is receive d , it is calibrate d and
s h oul d be p erformi ng wit h in t he s p ecification s h own in Sec-
tion 1 . T he following p roce d ure allows t he operator to be-
come familiar wit h t h e front p anel controls
an
d t h eir fu n c-
tions as well as how t hey
may be use d to d isplay transistor
or diod
e
c
h
a r acte r istics . T
h
is p roce d ur e may also be use d as
α ge n eral c h ec k of t he instr u ment's p erfo r mance . For α
check of t he instrument's op e r ation wit h res p ect to t he
s p ecification given in Section 1, t he Pe r formance C hec k an d
Calibration P roce d ure in Section 5 must be used .
1 . A pp ly powe r to t h e Ty p e 576 .
2 .
Allow
t he i n st ru ment to warm
up
for α few minutes .
Instr u ment s h oul d op erate with in s p ecifie d tolerances 5
minutes after it h as been tu r ned on .
3 . Set t he Ty p
e
576 an d Stan da r d Test Fixture front-
p anel controls as follows
:
RE
ADO U T Ι LLUM

F ully countercloc k wise
G R ATIC ULE Ι LLUM

Fully counterclockwise
I N T EN SITY

Fu lly cou nte r cloc k wise
FOC U S

Cente r e d
VER TICA L 1 mA