
Application Notes
AN1006
2002 Teccor Electronics
Thyristor Product Catalog
AN1006 - 11
http://www.teccor.com
+1 972-580-7777
3. Repeat Procedure 16. (Figure AN1006.17)
Figure AN1006.17 V
GT
 in Quadrant III = 820 mV
Procedure 19: V
GT
 – Quadrant IV [MT2 (-) Gate (+)]
To measure the V
GT
 – Quadrant IV parameter:
1. Set 
Polarity
 to (–).
2. Set 
Step/Offset Polarity
 by depressing 
Invert
 (release but-
ton on 577).
3. Set observed dot to top left corner of CRT grid by turning the 
Horizontal
 position knob. When testing is complete in Quad-
rant IV, return dot to original position.
4. Repeat Procedure 16.
Quadracs
Quadracs
 are simply triacs with an internally-mounted diac. As 
with triacs, 
Quadracs
 are bidirectional AC switches which are 
gate controlled for either polarity of main terminal voltage.
To connect the 
Quadrac
: 
1. Connect 
Trigger
 to
 Base Terminal 
(B).
2. Connect 
MT1
 to 
Emitter Terminal
 (E).
3. Connect 
MT2
 to
 Collector Terminal 
(C).
To begin testing, perform the following procedures.
Procedure 1: (+)V
DRM
, (+)I
DRM
, (-)V
DRM
, (-)I
DRM
Note: The (+) and (-) symbols are used to designate the polarity 
of MT2 with reference to MT1.
To measure the (+)V
DRM
, (+)I
DRM
, (-)V
DRM
, and (-)I
DRM
 parameter:
1. Set
Variable Collector Supply Voltage Range
 to appropri-
ate
 Max Peak Volts 
for device under test. (Value selected 
should be equal to or greater than the device’s V
DRM
 rating).
2. Set 
Horizontal
 knob to sufficient scale to allow v
iewing of 
trace at the required voltage level. (The 
100 V/DIV scale 
should be used for testing devices having a V
DRM
 rating of 
600 V or greater; the 
50 V/DIV
 scale for testing parts rated 
from 300 V to 500 V, and so on).
3. Set 
Mode
 to 
Leakage
.
4. Set 
Polarity
 to (+).
5. Set
Power Dissipation
 to 
0.5 W
. (
0.4 W
 on 370)
6. Set 
Terminal Selector
 to
 Emitter Grounded-Open Base.
7. Set 
Vertical
 knob to ten times the maximum leakage current 
(I
DRM
) specified for the device.
Note: The CRT readout should show 1% of the maximum
leakage current. The vertical scale is divided by 1,000 when
the leakage mode is used.
Procedure 2: (+)V
DRM
 and (+)I
DRM
To measure the (+)V
DRM
 and (+)I
DRM
 parameter:
1. Set 
Left-Right Terminal Jack Selector
 to correspond with 
the location of the test fixture.
2. Increase 
Variable Collector Supply Voltage
 to the rated 
V
DRM
 of the device and observe the dot on the CRT. (Read 
across horizontally from the dot to the vertical current scale.) 
This measured value is the leakage current. 
(Figure AN1006.18)
WARNING: Do NOT exceed V
DRM
/V
RRM
 rating of SCRs, triacs, 
or 
Quadracs
. These devices can be damaged.
Figure AN1006.18 (+)I
DRM
 = 51 nA at (+)V
DRM
 = 400 V
Procedure 3: (-)V
DRM
 and (-)I
DRM
To measure the (-)V
DRM
 and (-)I
DRM
 parameter:
1. Set 
Polarity
 to (–).
2. Repeat Procedures 1 and 2. (Read measurements from 
upper right corner of screen).
Procedure 4: V
BO
, I
BO
, 
V
BO
(
Quadrac
 Trigger Diac or Discrete Diac)
To connect the 
Quadrac
:
1. Connect 
MT1
 to 
Emitter Terminal
 (E).
2. Connect
 MT2
 to 
Collector Terminal 
(C).
3. Connect 
Trigger Terminal
 to
 MT2 Terminal
 through a 10
 
resistor.
To measure the V
BO
, I
BO
, and 
V
BO
 parameter:
1. Set
Variable Collector Supply Voltage Range
 to 
75 Max 
Peak Volts.
(
80 V
 on 370)
2. Set 
Horizontal
 knob to
 10 V/DIV
.
3. Set
Vertical
 knob to 
50 μA/DIV
.
4. Set
Polarity
 to 
AC
.
5. Set 
Mode
 to 
Norm
.
6. Set 
Power Dissipation
 to 
0.5 W
. (
0.4 W
 on 370)
50
mA
100m
PER
V
E
R
T
DIV
PER
H
O
R
I
Z
DIV
PER
S
T
E
P
()k
DIV
9m
PER
DIV
500
mV
VGT
50
nA
50
   V
PER
V
E
R
T
DIV
PER
H
O
R
I
Z
DIV
PER
S
T
E
P
()k
DIV
9m
PER
DIV
VDRM
IDRM