Scientific 5000 Series, Manual, Page: 264 / 360

APPENDIX H
13-24
Version 1.23
MODEL 5000 SERIES MANUAL
After firing, the Low Source latches the device on with a 1 amp current source. The
compliance voltage can be programmed to reduce the voltage used to latch the
device on. This feature can be useful in testing device that may be partially turned on
by the programmed I
BO
. It can be used to simulate actual circuit conditions under
which latching occurs.
Figure 13-9 SSOVP I
BO
TEST
13.1.8 V
BO
The V
BO
test is a measure of the highest voltage attained during the application of a
programmed 400
μSec current pulse (I
BO
). The test measures the peak voltage
obtained whether the device fired or not, therefore, if the test is to be used to
determine the peak voltage prior to firing, use the I
BO
test to confirm the device fires
at the programmed I
BO
level.
Note also that some devices exhibit a negative resistance characteristic prior to firing;
V
BO
therefore is not the firing voltage for this kind of device. Refer to manufacturers
specifications.
Figure 13-10 SSOVP V
BO
TEST
13.1.9 I
H
The I
H
test confirms the device holding current. To measure holding current, the
device must first be fired on with the 400
μSec pulse programmed I
BO
current( be e
certain this value is sufficient to fire the device). After firing, the Low Source applies
a current of two times the programmed I
H
, then reduces it to the programmed I
H
value
(soak time up to 25 mSecs can be added).
BO
I
BO
I
2OV(80V OPT)
COMPLIANCE
1A
BO
V
V
IH
GS
R BO
I
V
BO
I
MEASURE
V
0 to 20V (80V OPTIONAL)
PROGRAMMABLE COMPLIANCE