Tektronix CURVE-TRACER 576 Instruction Manual page 29

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28. Set the following Tyre 576 controls to:
MAX PEAK VOLTS
15
VARIABLE COLLECTOR
Fully Counterclockwise
SUPPLY
(The protective box may be removed if desired.)
29. Turn the VARIABLE COLLECTOR SUPPLY con-
trol until the diagonal trace reaches the center of the CRT
graticule. Pull out on the PEAK POWER WATTS switch
and set it to 220. Note that the diagonal trace lengthens as
the switch is turned through its range. Also note that th·
SERIES RESISTORS decrease as the maximum peak power
is increased.
30. Allow the MAX PEAK VOLTS switch and the
PEAK POWER WATTS switch to become interlocked and
switch to 75. Note that the maximum peak power value
remains at 220 and that the SERIES RESISTORS values
change.
31. Set the following Type 576 controls to:
HORIZONTAL
MAX PEAK VOLTS
VARIABLE COLLECTOR
SUPPLY
PEAK POWER WATTS
LEFT-OFF-RIGHT
.1 V COLLECTOR
15
Fully Counterclockwise
0.1
OFF
32. Remove the resistor from the diode adapter and re-
place it with a silicon diode. Align the diode so that its
cathode is connected to the emitter terminal.
33. Set the LEFT-OFF-RIGHT switch to RIGHT and
turn the VARIABLE COLLECTOR SUPPLY control clock-
wise. Note the display of the forward voltage characteristic
of the diode. (see Fig. 2-8).
34. Set the COLLECTOR SUPPLY POLARITY switch
to -(PNP). Note the display of the reverse voltage charac-
teristic of the diode (see Fig. 2-8).
:--
.--.-~~'T"'"""-z--.......-.......-....-"'T"'""""'
, Reverse Bias
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--.
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--.
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:--~4-~~--~4-~~--~4--i
--.
'
1--r-4-~_,--r-,_~_,--r-4--i
: I
~--+~~+-~~~~+-~~~~~~
, Forward Bias/
: - - t---+--+--+-t--±--t--t-1/t-+--4--i
·--r-4-~_,--r-,_~_,~r-4--i
:--~4-~-1--~4-~-fl/--+-4--i
:--r-4-~_,--r-,_~-+./~--+-4--i
--.
2
mA
...
H
0
100
R
I mv
z
s
50
T
E
nA
p
13
0'
Om YO
K
""
Fig. 2-8. Display of forward and reverse bias characteristics of a
signal diode.
©
Operating Instructions-Type 576
35. Set the following Type 576 controls to:
POLARITY
+
(NPN)
MODE
DC
Note that the display of the forward voltage diode char-
acteristic has become a spot. The spot indicates the current
conducted by the diode and the voltage across it.
36. Turn the VARIABLE COLLECTOR SUPPLY con-
trol counterclockwise. Note that the spot traces out the
diode characteristic.
37. Set the following Type 576 controls to:
VERTICAL 1 I-LA
HORIZONTAL
2 V COLLECTOR
Vertical POSITION
Display Centered
VARIABLE COLLEC-
TOR SUPPLY
MODE
LEFT-OFF-RIGHT
Fully Clockwise
NORM
LEFT
38. Adjust the LOOPING COMPENSATION control for
minimum trace width (see Fig. 2-9).
:--,-,--.-,--~"-.-,,-~,--,--:
: Incorrect Adjustment
·--~4--r~--~;--r~--~4--i
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~-~~~~~*+**~4*~~H#~4--
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o--~4--r~--~1-~_,--r-4--4
'
:--~4--+~--+-~-+~--+-~~
, Correct Adjustment
·--r-4--+_,--r-~-r~--T-~-4
...
H
~
2
~
v
Fig. 2-9. Adjustment of LOOPING COMPENSATION control.
39. Set the following Type 576 controls to:
VERTICAL 5 mA
Vertical POSITION Switch centered
VARIABLE COLLEC-
TOR SUPPLY
Fully Counterclockwise
POLARITY
AC
LEFT-OFF-RIGHT OFF
2-11