Tektronix CURVE-TRACER 576 Instruction Manual page 31

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added to the approximate estimate, yielding a value of 8.4
for the Zener voltage of the diode. The same process can
also be carried out using vertical display offset and magnifi-
cation.
Step Generator
47. Set the following Type 576 controls to:
DISPLAY OFFSET NORM (OFF)
Selector
0
CENTERLINE VALUE
HORIZONTAL
1 V COLLECTOR
Vertical POSITION
Switch centered
POLARITY +(NPN)
VARIABLE COLLEC-
Fully Counterclockwise
TOR SUPPLY
LEFT-OFF-RIGHT
OFF
48. Remove the diode adapter and replace it with a
transistor adapter (Tektronix Part No. 013-0098-02).
49. Place an NPN silicon transistor into the right tran-
sistor test socket of the universal transistor adapter.
50. Set the LEFT-OFF-RIGHT switch to RIGHT and
turn the VARIABLE COLLECTOR SUPPLY clockwise un-
til the peak collector-emitter voltage is about 10 volts.
51. Turn the AMPLITUDE switch until a step appears
on the CRT. Note that the greater the step amplitude, the
greater the collector current (see Fig. 2-12). Set the AMPLI-
TUDE for the minimum step amplitude which produces a
noticeable step in the display.
:--.-.--.-.--.-~-.-.--.-,-~--~
'
'
~4-~-1--+-1-~-1--+-~-4--~
5 I '
llt--1;/:::::f;:::::;+;:;;;~·
-1-m!:A4=1i-- :
·--~4--b~--+-1-~-1--+-~-4
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[--r-~~~~l_,
__
r-~-+-1--r-~~
·-- I
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•
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.2mA
: - - tt-/--t=I==I====F=f=F==*=i:::::i="f-i
,__ I ,___ --·
• .1 rnA
: -.JVFf:::::j::::::F:=:f::::f==F=t:==t==t=-l
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~--
,_..L........L....-1----L-L.....L......J.
50
l1A '-- --:
...
H
~
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~
v
~
o•
:::: 100
oov
Fig. 2-12. Collector current vs. Collector-Emitter voltage for various
settings of the AMPLITUDE switch.
52. Turn the NUMBER OF STEPS switch clockwise. Be
sure the PEAK POWER WATTS switch is set within the
power dissipation rating of the transistor being used. Note
the display of collector current vs. collector-emitter,voltage
for ten different values of base current (see Fig. 2-13A).
REV D JUL 1980
Operating Instructions-Type 576
·"
·--
--·
' lc vs. VeE I B
@
50 lJA/Step:
v
5
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E
·--
R mA
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T
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DIV
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--.
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.
--
'/
--.
0
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h
R
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f/,
--.
z
v
:(A)
DIV
.....
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...
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--.
s
50
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E IIA
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p
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--
--.
~
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o•
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9m
100
I - -
--·
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...
'
'
oov
L • •
--.
·--
--·
"
' lc vs. v 8 E
I B
@
50 lJA/Step:
v
5
'
E
.
--
--
.
R
mA
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--.
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0
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100
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:(a)
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50
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9m
100
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DIV
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--.
Fig. 2-13. (A)
Ic
vs. VeE for 10 steps of base current at 50 J,JA. per
step; (B)
Ic
vs. VBE for l 0 steps of lease current at 50 J,JA. per step.
53. Set the HORIZONTAL switch to .1 V BASE. Note
the display of the collector current vs. base-emitter voltage
for ten different values of base current (see Fig. 2-13B).
54. Set the VERTICAL switch to STEP GEN and the
HORIZONTAL switch to 1 V COLLECTOR. Note the dis-
play of the base current, one step per vertical division, vs.
the collector-emitter voltage (see Fig. 2-14A) .
55. Set the HORIZONTAL switch to .1 V Base. Note
the display of base current, one step per vertical division,
vs. base-emitter voltage (see Fig. 2-14B)
56. Set the VERTICAL switch to 5 rnA and the HORI-
ZONTAL switch to STEP GEN. Note the display of collec-
tor current vs. base-current, one step per horizontal division
(see Fig. 2-15).
57. Set the following Type 576 controls to:
HORIZONTAL
1 V COLLECTOR
RATE .5X
Note that the step rate is slower than the normal rate.
2-13