
AN1006
Application Notes
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+1 972-580-7777 
AN1006 - 18
2002 Teccor Electronics
Thyristor Product Catalog
Model 577 Curve Tracer Procedure Notes
Because the curve tracer procedures in this application note are written for the Tektronix model 576 curve tracer, certain settings must 
be adjusted when using model 577. Model 576 curve tracer has separate controls for polarity (AC,+,-) and mode (Norm, DC, Leakage), 
whereas Model 577 has only a polarity control. The following table shows the guidelines for setting Collector Supply Polarity when 
using model 577. (Figure AN1006.28)
One difference between models 576 and 577 is the Step/Offset 
Polarity setting. The polarity is inverted when the button is 
depressed on the Model 576 curve tracer. The Model 577 is 
opposite 
 the 
Step/Offset Polarity
is “inverted” when the button 
is extended and “Normal” when the button is depressed. The 
Step/Offset Polarity is used only when measuring I
GT
 and V
GT
 of 
triacs and 
Quadracs
 in Quadrants l through lV.
Also, the Variable Collector Supply Voltage Range and Power 
Dissipation controls have different scales than model 576. The 
following table shows the guidelines for setting Power Dissipation 
when using model 577.
Although the maximum power setting on model 576 curve tracer 
is 220 W (compared to 100 W for model 577), the maximum col-
lector current available is approximately the same. This is due to 
the minimum voltage range on model 577 curve tracer being 
6.5 V compared to 15 V for model 576. The following table shows 
the guidelines for adapting Collector Voltage Supply Range set-
tings for model 577 curve tracer procedures:
Model 576
Model 577
If using Leakage mode along with polarity setting of +(NPN) and -(PNP),
[vertical scale divided by 1,000],
set 
Collector Supply Polarity
 to either 
+DC
 or 
-DC
, depending on polarity setting 
specified in the procedure. The vertical scale is read directly from the scale on the 
control knob.
set 
Collector Supply Polarity
 to either 
+DC
 or 
-DC
 depending on polarity 
specified.
set 
Collector Supply Polarity
 to either 
+(NPN)
 or 
-(PNP)
 per specified procedure.
set 
Collector Supply Polarity
 to 
AC
.
If using DC mode along with either +(NPN) or -(PNP) polarity,
If using Norm mode along with either +(NPN) or -(PNP) polarity,
If using Norm mode with 
AC
 polarity,
Model 576
Model 577
If power dissipation is 0.1 W,
If power dissipation is 0.5 W,
If power dissipation is 2.2 W,
If power dissipation is 10 W,
If power dissipation is 50 W,
If power dissipation is 220 W,
set at 0.15 W.
set at 0.6 W.
set at 2.3 W.
set at 9 W.
set at 30 W.
set at 100 W.
Model 576
Model 577
If voltage range is 15 V,
set at either 6.5 V or 25 V, depending on parameter 
being tested. Set at 6.5 V when measuring V
 (to 
allow maximum collector current) and set at 25 V 
when measuring I
GT
 and V
GT
.
set at 100 V.
set at 1600 V.
If voltage range is 75 V,
If voltage range is 1500 V,