Tektronix 576 - Page 37

Ι DSS
Op
erati ng I n st r uctions-Type 576
Drain-source current with zero V GS is measured
from t
h
e common-sou r ce family, wit h
th e Terminal Selecto r switc h set to B AS E T ERM S H O
R T . It sh oul d be measured above
th e k nee of th ecu r ve .
P i n c h -Off V oltage (Vp)

P inc h -off voltage (Vp) can be measure d by increasing
th e d e p letio n voltage wit h t h e
O FF S E T MUL T co nt r ol a n d th e A MPL IT U D E switc
h u ntil th e s p ecified p inc h -off cur-
rent is reach ed by t he zero step (ze r o step only is o btained by pressing SI
N G LE button) .
T hus t he p
inc h -off voltage is the setti ng of t he O FFS E T MUL T cont
r
ol times
t
h e setting
of t h
e
A MPL IT UD
E switc h .
B VGSS

Gate-source
brea k d own voltage with t he d r ain s horte d to
t
h
e source can be measured by
putti n g t h e
gate lead of t he d evice i n t he d rain terminal of t he test soc
k et, t he source lead
in t he
gate
termi
n al and t he d rai n lea d in t he source te r minal .
Set t
h
e Terminal Selector
switch to B AS E T ERM SHORT
an d reverse t h e collector supp ly
p
olarity . T
h is measure-
ment s h ould not be madeon an
ins u late
d
-gate device .
UN I JUN CTIO NT R AN SISTO RS
R e quired Ty p e 576 Co n trol
Settings
ΙΕ
Vs-
VE B 1
Fo r s p ecified
Vg2
Vg
1
Some Commo n M easureme
n ts
T h
e intrinsic standoff ratio is
VP
-V
EB t
/
VB 2 VB 1 . In measuring
Υ l ,
VB 2B1
is deter-
mine d by t h e O FF S E
T MUL T co n trol and t h
e AMPL IT UDE switch . VB 2 B t
may be
measure d by setting t h
e H
O
R IZO N TA L switch to t he BAS
E range . V ρ is d
etermi n e d by
app lying voltage between
t he emitter an d t he base,
te r minals using t h
e VA R IA BLE
CO LLE CTO R S UPPL Y
control . Vp is t h e voltage
at w h ic h t he emitter-base,
j un ction
becomes forwar d
biased .
V E B ,,
t he turn
on voltage of t he emitte
r -
b
ase, ju nction
is
determine d by
setting t he Te r mi n al Selector
switc h to BAS
E T ERM OPEN .
2- 29
Co n trol
Req uire d Setting
H O
R
IZON
TA L CO LLE CTO R
P
OL A
RITY +( ΝΡΝ
)
PEAK
P O WER W ATTS L ess t h
an maximum p ower rating of d evice
A MPL IT UD E
V oltage
O FF S
E T AID
STEP F A M I LY
O FF (SI NGLE )
Te r mi n al Selecto r
B AS E T ERM ST EP G EN
ENNEEMENNE
R
r Α
01300000000
O 7 rv
MINEMENEEMN
PER Η
MINNNEENNNNI
01100000000
PER
MINENEEMENN
s Ι
Τ
" Ε
`
Ρ `%
MINEMEMEMEN
. ρ (
EMENESEENN