
Application Notes
AN1006
2002 Teccor Electronics
Thyristor Product Catalog
AN1006 - 15
http://www.teccor.com
+1 972-580-7777
To continue testing, perform the following procedures.
Procedure 9: V
TM(Forward)
To measure the V
TM (Forward)
 parameter:
1. Set
Left-Right Terminal Jack Selector
 to correspond with 
the location of the test fixture.
2. Increase
Variable Collector Supply Voltage
 until current 
reaches rated I
T(peak)
, which is 1.4 times the I
T(RMS)
 rating of 
the sidac.
Note: Model 370 current is limited. Set to 400 mA. Check for 
1.1 V MAX.
WARNING: Limit test time to 15 seconds. 
3. To measure V
TM
, follow along horizontal scale to the point 
where the trace crosses the I
T(peak)
 value. This horizontal dis-
tance is the V
TM
value. (Figure AN1006.25)
Figure AN1006.25 V
TM (Forward)
 = 950 mV at I
 = 1.4 A
Procedure 10: V
TM(Reverse)
To measure the V
TM (Reverse)
 parameter:
1. Set
Polarity
to (–).
2. Repeat Procedure 8 to measure V
TM(Reverse)
.
Diacs
Diacs are voltage breakdown switches used to trigger-on triacs 
and non-sensitive SCRs in phase control circuits.
Note: Diacs are bi-directional devices and can be connected in 
either direction.
To connect the diac:
1. Connect one side of the diac to the
 Collector Terminal
 (C).
2. Connect other side of the diac to the 
Emitter Terminal
 (E).
To begin testing, perform the following procedures.
Procedure 1: Curve Tracer Setup
To set the curve tracer and begin testing: 
1. Set 
Variable Collector Supply Voltage Range
to 
75 Max 
Peak Volts. 
(
80 V
 on 370)
2. Set 
Horizontal
knob to sufficient scale to allow viewing of 
trace at the required voltage level (
10 V to 20 V/DIV
 depend-
ing on device being tested).
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)
7. Set 
Terminal Selector
 to
 Emitter Grounded-Open Base.
Procedure 2: V
BO
To measure the V
BO
 parameter:
1. Set 
Left-Right Terminal Jack Selector
 to correspond with 
the location of the test fixture.
2. Set 
Variable Collector Supply Voltage
 to 
55 V
 (
65 V
 for 
370) and apply voltage to device under test (D.U.T.), using 
Left-Right-Selector Switch
. The peak voltage at which cur-
rent begins to flow is the V
BO
 value. (Figure AN1006.26)
Figure AN1006.26 (+)V
BO
 = 35 V; (-)V
BO
 = 36 V; (±)I
BO
 < 15 μA;
(-)I
BO
 < 10 μA and Cannot Be Read Easily
Procedure 3: I
BO
To measure the I
BO
 parameter, at the V
BO
 point, measure the 
amount of device current just before the device reaches the 
breakover mode. The measured current at this point is the I
BO
value.
Note: If I
 is less than 10 μA, the current cannot readily be seen 
on the curve tracer.
Procedure 4:
 
V
BO(Voltage Breakover Symmetry)
To measure the 
V
BO (Voltage Breakover Symmetry)
 parameter:
1. Measure positive and negative values of V
BO
 as shown in 
Figure AN1006.26.
2. Subtract the absolute value of V
BO
(-) from V
BO
(+).
The absolute value of the result is:
V
BO
 = [ I +V
BO
 I - I -V
BO
 I ]
500
mA
500
mV
PER
V
E
R
T
DIV
PER
H
O
R
I
Z
DIV
PER
S
T
E
P
()k
DIV
9m
PER
DIV
VTM
IPK
50
  A
10
V
PER
V
E
R
T
DIV
PER
H
O
R
I
Z
DIV
PER
S
T
E
P
()k
DIV
9m
PER
DIV
+VBO
+IBO
 IBO
 VBO