Tektronix CURVE-TRACER 576 Instruction Manual page 46

Operating Instructions-Type 576
~
(Static)
~
(Small Signal)
VeE (Sat)
IC vs. VBE
ICEO and BVcEO
ICES and BVcES
ICER and BVCER
Some Common Measurements
The static forward current transfer ratio (emitter grounded), hFE, is lc;IB.
The small-signal short-circuit forward current transfer ratio (emitter grounded), hfe, is
6lc/AIB. To determine hfe at various points in a family of curves, multiply the vertical
separation of two adjacent curves by the
~
0 R gm PER D IV readout. To make a more
accurate measurement, see steps
69
through 74 of the First Time Operation instructions.
Saturation current and voltage is measured by expanding the display of the saturation
region of the device by decreasing the horizontal deflection factor with the HORIZON-
TAL switch or the DISPLAY OFFSET MAGNIFIER. Saturation current can be adjusted
to the desired operating point with the AMPLITUDE switch.
Base-emitter voltage can be measured by setting the HORIZONTAL switch to the BASE
range.
Collector-emitter leakage current and collector-emitter breakdown voltage (base open) are
measured by setting the Terminal Selector switch to BASE TERM OPEN (OR EXT). For
small leakage currents set the MODE switch to LEAKAGE (EMITTER CURRENT). To
measure breakdown voltage, increase both the horiLontal deflection factor and the collec-
tor supply voltage.
Collector-emitter leakage current and collector-emitter breakdown voltage (base shorted
to emitter) are measured the same as I CEO and BVcEO except that the Terminal Selector
switch is set to BASE TERM SHORT.
Collector-emitter leakage current and collector-emitter breakdown voltage (with a speci-
fied resistance between the base terminal and the emitter terminal) are measured the same
as ICEO and BVcEO except that a specified resistance is connected between the base
terminal and the emitter terminal.
Common-Base Family
·--
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500
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T
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c h -
JJA
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--.
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Collector
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--·
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H
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Display
0
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Supply
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Amp. I
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Rs
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w
CX: (Small Signal)
2-28
E~·
.
--·
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Step
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s 500
T
Generator '
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JJA
--·
p
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--·
' '
e
--·
Om
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DOV
.
--
--.
lc
vs.
Vee
for
different values of IE
Some Common Measurements
The small-signal short-circuit forward current transfer ratio (base grounded), hfb, can be
measured from the common-base family display but is determined most easily by calcu-
lating it from the equation
ex
=~/1 + ~.
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