Tektronix 576 - Page 35

β
(Static)
β (Small Signal)
VC E (Sat)
IC Vs .
VBE
ICE O
a
n d Β VςΕΟ
IC E S
an
d BVς
ES
IC ER
an
d BV ς
E R
OC
(Small Signal)
Some Common
M
easu
r ements
OperatingInstructions-Type 576
T h e static forwar d cu rrent transfer ratio
(emitter grounded), h FE , is IC/113-
The small-signal s h ort-circuit forwar d
current transfer ratio (emitter grounded), h f e , is
οΙς
/'n'
ΙΒ
.
To d etermine h f e at
various p oints in α family of curves, multip ly t h e vertical
separation of two ad j acent curves by t h e β O R
gm
PER D I V rea dou t . To ma k e α more
accurate measurement, see ste p s 69 t h roug h 74
of t h e F irst Time O p eration instructions .
Saturatio n current an d voltage
is measure d by ex p anding t he d is p lay of t he saturation
region of t h
e
device by d
ecreasing t he h orizontal d eflection factor with
t
h
e H
O
RIZON-
TA L switch or t he DIS PL AYO FF S
ET
M AG
N I F I ER . Saturation current ca n be ad j uste
d
to t he d esired op erating point
with t he A M PL IT U D E switch .
B ase-emitter voltage can be
measure
d
by setting t h e H O R IZO NTA L switch to
t he B ASE
r ange .
Collector-emitter lea k age
current
and
collector-emitter brea k d own voltage (base op
en) are
measured by setti ng t h e Terminal
Selector switch to B AS E T ERM OPEN (O R
ΕΧΤ ) . F or
small lea k age curren ts
set
t h
e M
OD
E switch to LE A K AG E (EM ITT ER C UR
RENT) . To
measure brea k down
voltage, increase bot h t h e h orizontal d
eflection factor a nd t h e collec-
tor su p p ly voltage .
Collector-emitter lea k age current an d
collector-emitter breakd own voltage
(base s horted
to emitter) are measure d t he same as ΙςΕΟ an
d Β VςΕΟ exce p t t h at t he
Terminal Selector
switch is set to B AS E T ERM S H O R T .
Collector-emitter lea k age cu r rent an d
collector-emitter break down voltage (wit
h α s p eci-
fie d
resistance between t he base terminal and
t he emitter terminal) are measured
t h e same
as
ΙςΕΟ a n dΒ V ςΕΟ except t h at α s p
ecifie d resistance is co n necte d
between
t
he
b
ase
terminal an d t he emitter terminal .
Common- B ase F amily
kimii
MENEEMEMEN
IC
vs .
νςΒ
fo
r
d iffere n
t
val u es of
ΙΕ
PER
5
Γ - ι t
~!
ΟΝ

~
ΓΣ "
PER
Η
ο
Ρ
Ι
οιν
1R
PER
Some Common M easureme n ts
T he small-signal s h ort-circuit forwar d
current transfer ratio (base groun d ed),
h fb, can be
measure d from t h e commo
n -base family d is p lay bu t is determine d
most easily by calcu-
lating it from t h
e eq
u
ation

Οί = β /1 + β .
2-27